1.

The present case is one of a now long series of cases concerning the interpretation of the principle of non-discrimination of fixed-term workers in connection with various rules of Spanish employment and public service legislation. The Court is being asked, in essence, to clarify whether that principle requires that additional remuneration for grade which is awarded to (permanent) public officials under the legislation of an autonomous region of Spain is also to be granted to fixed-term contract staff in the public administration. In this regard, it must be ensured that the protective purpose of the principle of non-discrimination of fixed-term workers is reconciled with the inherent characteristics of public service law and the organisational autonomy available to the Member States in this area.

2.

Against this background, in examining the question referred for a preliminary ruling, attention must be paid, on the one hand, to the comparability of the specific situations of fixed-term contract staff and permanent public officials and, on the other, to the inherent characteristics of public service law as a possible justification for a difference in treatment of the two groups.

3.

The EU law framework for this case is established by Council Directive 1999/70/EC of 28 June 1999 concerning the framework agreement on fixed-term work concluded by ETUC, UNICE and CEEP. ( 2 ) According to its Article 1, that directive puts into effect the Framework Agreement on fixed-term work (also ‘the Framework Agreement’) which was concluded on 18 March 1999 between three general cross-industry organisations (ETUC, UNICE and CEEP) and is annexed to the directive.

4.

The Framework Agreement aims, inter alia, to ‘improve the quality of fixed-term work by ensuring the application of the principle of non-discrimination’. ( 3 ) Underlying it in this regard is the consideration ‘that contracts of an indefinite duration are, and will continue to be, the general form of employment relationship between employers and workers’. ( 4 ) At the same time, however, the Framework Agreement recognises that fixed-term employment contracts ‘are a feature of employment in certain sectors, occupations and activities which can suit both employers and workers’. ( 5 )

5.

The Framework Agreement’s scope is determined in Clause 2(1) thereof:

‘This agreement applies to fixed-term workers who have an employment contract or employment relationship as defined in law, collective agreements or practice in each Member State.’

6.

Clause 3 of the Framework Agreement contains the following ‘definitions’:

7.

Clause 4 of the Framework Agreement is headed ‘Principle of non-discrimination’ and includes the following provision:

…

8.

Article 3(1) of Texto Refundido del Estatuto del Personal al Servicio de las Administraciones Públicas de Navarra (Consolidated Text of the Staff Regulations for the Public Administration of Navarre) of Decreto Foral Legislativo 251/1993, que aprueba el Texto Refundido del Estatuto del Personal al Servicio de las Administraciones Públicas de Navarra (Regional Legislative Decree 251/1993 approving the Consolidated Text of the Staff Regulations for the Public Administration of Navarre, ‘DFL 251/93’) provides that ‘staff working for the Public Administration of Navarre shall comprise: (a) Public officials; (b) Temporary staff; (c) Contract staff’, with Article 3(4) providing that contract staff may be employed ‘under an administrative contract or an employment contract’.

9.

Article 12 of DFL 251/93 stipulates that officials of the Public Administration of Navarre are to be assigned to the levels referred to therein, depending on entry qualifications and the duties they perform.

10.

Article 13 of DFL 251/93 provides as follows:

‘1.   Each of the levels referred to in the previous article shall comprise seven grades.

2.   New entrants shall be assigned to grade 1 of the appropriate level.

3.   Officials may by degrees progress from grade 1 to grade 7 of their respective level in accordance with Article 16 of these Regulations.’

11.

Article 14 et seq. of DFL 251/93 regulate the career path for public officials, under which officials may achieve ‘promotion from one of the levels defined in Article 12 to higher levels, and progression to higher grades and categories within each level’.

12.

Article 16 deals specifically with grades and provides as follows:

‘1.   Officials may progress successively from grade 1 to grade 7 of their respective level, regardless of the specialism of their academic qualification, training or profession.

2.   Grade progression shall take place annually as follows: (a) It is an essential requirement for progression to a higher grade that an official should have spent at least 2 years in the previous grade; (b) no official may remain for more than 8 years in the same grade, except for those officials who have reached grade 7; (c) without prejudice to the previous paragraphs, 10% of the officials in grades 1 to 6 inclusive shall progress to the next grade in order of length of service; (d) Up to 10% of officials in grades 1 to 6 inclusive may progress to the next grade through a competition based on qualifications, which shall be held in accordance with regulations issued by the administration.’

13.

However, this system of grade progression in Article 16 is temporarily suspended by the Fourth Transitional Provision of DFL 251/93, which states as follows:

‘1.   With effect from 1 January 1992 and until the regulations referred to in Article 13 of the Ley Foral 5/1991 de 26 de febrero, de Presupuestos Generales de Navarra para 1991 (Regional Law 5/1991 of 26 February 1991 on the General Budget for Navarre for 1991) concerning changes to the current grade and length-of-service arrangements shall have been adopted, the system of grade progression established in Article 16 of these Regulations is temporarily suspended, and from that date those arrangements will be applied individually to each official, in accordance with his length of service in the corresponding grade, as follows:

2.   As a consequence of the provisions in the previous paragraph, from the abovementioned date, and likewise temporarily, in the case of progress to a higher level within the same Administration in accordance with Article 17 of these Regulations, the same grade and length of service shall be maintained in that grade as were held in the level from which the official was promoted.’

14.

On progression to a higher grade, additional remuneration is payable in that Article 40(2) of DFL 251/93 provides that officials’ basic personal salary payments comprise the following:

Basic personal salary payments are an acquired right vested in public officials.’

15.

Article 42 sets out a table with the percentages by which the starting salary for the level is to be increased for each grade:

‘Without prejudice to the provisions of Article 17(2), the additional remuneration for grade shall consist of the following percentage of the relevant starting salary:

16.

DFL 251/93 also lays down the rules governing contract staff who are not public officials; Article 93 states that ‘staff employed under an administrative contract shall be governed by provisions made in regulations and by the terms of the relevant contract’.

17.

The regulations implementing the provisions governing staff employed under an administrative contract are contained in Decreto Foral 68/2009 (Regional Decree 68/2009, ‘DF 68/2009’), which governs employment of staff under administrative contracts in the Public Administration of Navarre. With regard to remuneration for staff employed under an administrative contract, Article 11 of DF 68/2009 as amended by Decreto Foral 21/2017 of 29 March 2017 stipulates as follows:

‘Staff employed under an administrative contract shall receive the appropriate salary for the post they occupy or the duties they perform, the length-of-service supplement and the family allowance. The additional remuneration for grade shall be excluded as a basic personal salary payment inherent in the status of public official.’

18.

The applicant in the main proceedings, Mr Ustariz Aróstegui, has worked as a teacher for the Departamento de Educación del Gobierno de Navarra (Ministry of Education of the Government of Navarre) under an administrative contract at various educational establishments since September 2007.

19.

On 1 July 2016, Mr Ustariz Aróstegui applied to the Ministry of Education for the award and payment of additional remuneration for grade with retroactive effect. In a written application dated 18 October 2016, he lodged an administrative appeal against the refusal of his application due to administrative silence; the appeal was dismissed in Orden Foral (Regional Order) 168E/2016 of the Consejero de Educación del Gobierno de Navarra (Minister for Education of the Government of Navarre) of 23 December 2016. On 28 February 2017, he lodged an appeal in administrative proceedings against that Regional Order at the referring court. That court has referred the following question to the Court:

‘Must Clause 4 of the Framework Agreement on fixed-term work concluded by ETUC, UNICE and CEEP approved by Council Directive 1999/70/EC of 28 June 1999 be interpreted as precluding a regional legislative provision, such as that at issue in the main proceedings, which expressly excludes the award and payment to staff employed by the Public Administration of Navarre who are classified as ‘employed under an administrative contract’ (a fixed-term contract) of particular additional remuneration, on the grounds that the additional remuneration in question constitutes remuneration for promotion and development in a professional career that is open only to staff classified as ‘established public officials’ (with a contract of indefinite duration)?’

20.

In the preliminary ruling proceedings before the Court, written observations were submitted by Mr Ustariz Aróstegui and the Departamento de Educación del Gobierno de Navarra, as parties in the main proceedings, and the Kingdom of Spain, Portugal and the European Commission. The same parties, with the exception of Portugal, were also represented at the hearing on 30 January 2019.

21.

By its question, the referring court wishes to know, in essence, whether it constitutes discrimination prohibited by EU law if fixed-term public-sector contract staff are denied legal entitlement to the grant of additional remuneration for grade because the applicable legislation of the autonomous region reserves such entitlement for permanent public officials.

22.

The background to this question is that the Staff Regulations for the Public Administration of Navarre transitionally replaced the system of grade progression applicable to public officials with corresponding additional remuneration, the calculation of which is essentially based on the completion of a certain period of service.

23.

The Framework Agreement is applicable to fixed-term employment contracts. This is clear from its title and is confirmed by the definition of its scope in Clause 2(1). Under that provision, the Framework Agreement applies to fixed-term workers who have an employment contract or employment relationship as defined in law, collective agreements or practice in each Member State.

24.

It is common ground that the main proceedings concern a fixed-term employment relationship, as envisaged for contract staff in the Autonomous Region of Navarre under the rules of the Staff Regulations for the Public Administration of Navarre.

25.

The Court has also already made clear that ‘the provisions of the Framework Agreement can apply to fixed-term employment contracts and relationships concluded with public authorities and other public-sector bodies’ ( 6 ) and that individuals are able to rely directly upon Clause 4(1) of the Framework Agreement before national courts against such authorities or bodies. ( 7 )

26.

It must also be examined whether the contested additional remuneration for grade also comes under ‘employment conditions’ within the meaning of Clause 4(1) of the Framework Agreement. According to the Court’s consistent case-law, the criterion of employment is decisive, that is to say the employment relationship between a worker and his employer. ( 8 )

27.

According to the Court’s settled case-law, Clause 4 of the Framework Agreement is intended to prevent an employer using such an employment relationship to deny those workers rights which are recognised for permanent workers. ( 9 ) In order to take account of this objective, the Court rejects a restrictive interpretation of that provision. ( 10 )

28.

Based on this understanding, the Court has ruled with regard to employment relationships in the public service that the concept of ‘employment conditions’ within the meaning of Clause 4(1) of the Framework Agreement covers, for example, length-of-service allowances awarded for each 3 years of service, ( 11 ) six-yearly continuing professional education increments, ( 12 ) rules concerning periods of service to be completed in order to be classified in a higher salary grade or calculation of the periods required to have performance assessed each year ( 13 ) and remuneration supplements in connection with participation in evaluation plans. ( 14 )

29.

In the present case, as a rule, it is for the referring court to determine the nature and the objectives of the contested additional remuneration. ( 15 ) Nevertheless, it is apparent from the statements made by the referring court and from the consistent statements made by the participants at the hearing that the contested additional remuneration constitutes a component of remuneration the grant of which depends on the respective period of service completed and is thus linked to the decisive criterion of employment. The contested additional remuneration for grade can thus be subsumed under the concept of ‘employment conditions’ within the meaning of Clause 4(1) of the Framework Agreement.

30.

It is common ground in this case that contract staff are treated differently from public officials in so far as they are not entitled to the grant of additional remuneration for grade under the relevant legislation of Navarre.

31.

A difference in treatment also cannot be ruled out on the ground that under the applicable legislation of Navarre the contested additional remuneration for grade is reserved for public officials and is thus denied not only to fixed-term contract staff, but possibly also to non-statutory permanent workers in the public service. ( 16 ) For the purposes of establishing a difference in treatment within the meaning of Clause 4(1) of the Framework Agreement it is sufficient that ‘fixed-term workers’ are treated less favourably than ‘comparable permanent workers’. It is by no means necessary that all workers in fixed-term employment should be in a more unfavourable situation than all workers in permanent employment. ( 17 )

32.

However, according to the Court’s settled case-law, the principle of non-discrimination, of which Clause 4(1) of the Framework Agreement is a specific expression, requires that comparable situations should not be treated differently and different situations should not be treated alike, unless such treatment is objectively justified. ( 18 )

33.

In that regard, the principle of non-discrimination has been implemented and specifically applied by the Framework Agreement solely as regards differences in treatment as between fixed-term workers and permanent workers in a comparable situation. ( 19 )

34.

It must therefore be examined, first of all, whether the situation of public officials and the situation of fixed-term contract staff are comparable in terms of the specific employment in question at the institution concerned.

35.

The Portuguese Government and the Regional Government of Navarre have doubts as to whether fixed-term contract staff are comparable to public officials as permanent workers. They rely on the Court’s judgment in Pérez López, ( 20 ) according to which any difference in treatment which is not based on the fixed-term or permanent nature of the employment relationship, but on whether it is statutory or contractual, is not covered by the principle of non-discrimination established by the Framework Agreement. However, this fails to acknowledge that the finding relates to ‘any difference in treatment between specific categories of fixed-term workers’. The present case concerns a difference in treatment between fixed-term contract staff and permanent public officials.

36.

According to the Court’s settled case-law, in order to assess whether the persons concerned are engaged in the same or similar work for the purposes of the Framework Agreement, it must be determined, in accordance with Clauses 3(2) and 4(1) of the Framework Agreement, whether, in the light of a number of factors, such as the nature of the work, training requirements and working conditions, those persons can be regarded as being in a comparable situation. ( 21 )

37.

However, it is in turn for the referring court, which alone has jurisdiction to assess the facts, to carry out that examination. ( 22 ) It must assess whether Mr Ustariz Aróstegui was in a situation comparable to that of permanent public officials taken on by the same employer during the same period.

38.

In the present case, it must be assumed that the fixed-term contract employee in question, in the light of the specific teaching activities to be carried out (in particular the nature of his work, training requirements and working conditions), is in the same situation as a permanent public official in the same educational establishment. The referring court expressly states in this regard that ‘in the case at issue here, there is no difference between the duties and work performed by a teacher who is a public official and a teacher employed under an administrative contract, and no reservation or exclusion applicable, nor is there any difference in their professional obligations’.

39.

As I have already said several times elsewhere, ( 23 ) however, the examination of whether the situations are comparable cannot stop at a general comparison of the respective positions of fixed-term workers and permanent workers in the institution in question. The decisive factor, after all, is whether fixed-term workers and permanent workers are in a comparable situation from the point of view in particular of the matter at issue in the case in question.

40.

The matter at issue in the present case is the grant of additional remuneration for grade. According to the referring court, the law establishes that grades are one of the mechanisms for promotion within the public administration profession, and according to the legislation this profession is restricted to established public officials and is not open to other staff employed by the Public Administration of Navarre. Accordingly, Article 11 of DF 68/2009 expressly excludes the grant of additional remuneration for grade to contract staff in the public administration. Subject to a definitive assessment by the referring court, the difference in treatment in respect of additional remuneration for grade which must be considered to exist is thus not linked to the fixed-term or permanent nature of the employment relationship, but to whether the workers being compared are statutory or contractual ( 24 ) staff.

41.

According to the referring court, the purpose of the additional remuneration for grade is to reward promotion, progression and development in that profession. Additional remuneration for grade thus constitutes a component of remuneration reflecting grade progression. However, the relevant rule here is not the basic provision laid down in Article 16 of DFL 251/93, but the Fourth Transitional Provision of DFL 251/93. The representative of the Regional Government of Navarre stated as the reason for the ‘temporary’ suspension of the promotion system under Article 16 of DFL 251/93 on 1 January 1992 by the Fourth Transitional Provision of DFL 251/93 that the public employer and the trade unions had not yet been able to reach agreement on the implementation of the selection procedure under Article 16(2)(d) of DFL 251/93. This explains why the Fourth Transitional Provision of DFL 251/93 links the grant of the contested additional remuneration only to the completion of a certain period of service. The referring court points out in this connection that progression to the next grade under the Fourth Transitional Provision of DFL 251/93 comes about purely with the passage of time and ‘automatically’.

42.

Against this background, there cannot be any serious doubt over the comparability of the situations having regard to the specific matter at issue. The grant of the contested additional remuneration depends solely on the respective period of service completed; in addition, the grant of that remuneration, which is not formally accompanied by any reclassification of the public official concerned, has no discernible connection with the system of progression or professional advancement. According to the representative of the Regional Government of Navarre, the grant of additional remuneration has no effect on the functions performed or even on any possibility of promotion to a higher level. The matter at issue is ultimately thus a component of remuneration, and not career progression.

43.

Accordingly, subject to a definitive assessment by the referring court, the situations must also be considered to be comparable having regard to the specific matter at issue in so far as the applicant in the main proceedings satisfies the substantive condition relating to the period of service completed.

44.

Against this background, a difference in the treatment of comparable situations is present where fixed-term public-sector workers are denied the grant of additional remuneration on completion of a certain period of service, whereas permanent public officials in such a situation have a statutory right to such additional remuneration.

45.

It remains to be examined, as the central problem in the present case, whether there are objective grounds to justify the difference in treatment of fixed-term public-sector workers and permanent public officials in respect of the grant of the contested additional remuneration for grade.

46.

According to the Court’s settled case-law, the term ‘objective grounds’, within the meaning of Clause 4(1) of the Framework Agreement, must be understood as not permitting a difference in treatment between fixed-term workers and permanent workers to be justified on the basis that the different treatment is provided for by a general or abstract measure, such as a law or a collective agreement. ( 25 ) In order to justify the difference in treatment which exists between public officials and fixed-term contract staff in respect of additional remuneration for grade under the Fourth Transitional Provision of DFL 251/93 it is not therefore sufficient to describe the contested additional remuneration as part of the ‘basic personal salary payments … vested in public officials’. ( 26 )

47.

Rather, the concept of ‘objective grounds’ requires, according to equally settled case-law, the unequal treatment found to exist to be justified by the presence of precise and specific factors, characterising the employment condition to which it relates, in the specific context in which it occurs, and on the basis of objective and transparent criteria, in order to ensure that that unequal treatment in fact responds to a genuine need, is appropriate for the purpose of attaining the objective pursued and is necessary for that purpose. Those factors may be apparent, in particular, from the specific nature of the tasks for the performance of which fixed-term contracts have been concluded and from the inherent characteristics of those tasks or, as the case may be, from pursuit of a legitimate social-policy objective of a Member State. ( 27 )

48.

It is true that the principles governing public service employment — for example, the ‘established post’ principle, the model of the career civil servant and the requirement of successful completion of a selection procedure as a condition of indefinite employment — are not without consequence from the point of view of the practical application of the provisions of the Framework Agreement. ( 28 ) This is because the Framework Agreement expressly recognises, after all, ‘that … detailed application [of the Agreement’s principles and minimum requirements] needs to take account of the realities of specific national, sectoral and seasonal situations’. ( 29 )

49.

The Court has recognised to that effect that, in view of the discretion enjoyed by Member States as regards the organisation of their own public administrations, they can, in principle, without acting contrary to Directive 1999/70 or the Framework Agreement, lay down period-of-service conditions for access to certain posts, restrict access to internal promotion solely to established career civil servants and require those civil servants to provide evidence of professional experience corresponding to the grade immediately below the grade concerned by the selection procedure. ( 30 )

50.

The Court further considered the exclusion of fixed-term, temporary public officials from six-yearly continuing professional education increments merely on the ground that they do not belong to a category to have no objective justification. ( 31 )

51.

This shows that not all differences in treatment between fixed-term workers and comparable permanent workers can be justified generally by reference to the sectoral particularities of the public service, ( 32 ) but only those which are genuinely and specifically dictated by the aforementioned particularities. ( 33 ) Accordingly, the grounds cited by the Member States for a difference in treatment of fixed-term workers in the public service cannot be derived in a general and abstract manner from the limited term of the employment relationship and any resulting non-membership of a category. ( 34 ) Such grounds must instead serve to take due account of different requirements in connection with the specific employment, for example, based on the specific nature of the tasks to be performed or the characteristics of those tasks. ( 35 )

52.

It must be examined below whether an objective ground to justify the difference in treatment found to exist is evident, on the one hand, from the particularities of public service employment in Navarre and, on the other, the conditions under which the completed period of service is taken into consideration.

53.

In the present case there is nothing to indicate that the unequal treatment at issue responds to a genuine need, for example, in relation to the implementation of principles of public service employment in Navarre, or that it is appropriate for the purpose of attaining the objective pursued and is necessary for that purpose.

54.

The Spanish Government, the Portuguese Government and the Regional Government of Navarre set out the particularities of the public service as enshrined not least in the Spanish Constitution. ( 36 ) In the view of those parties, those particularities would require a legal entitlement to additional remuneration for grade to be granted only to permanent public officials, but not to fixed-term contract staff in the public service. It is also argued that employment of contract staff in the public service is not, in principle, on a permanent basis and requires a specific justification in the form of proof of need in respect of a precise post to be filled, which necessarily runs counter to participation in the career system and consequently precludes the enjoyment of financial benefits connected with that system.

55.

This argument is not convincing because it is inconsistent. The exclusion at issue in this case applies not just to fixed-term contract staff, but to all non-statutory workers. Even if only fixed-term contract staff were subject to the exclusion, reliance on the mere temporary nature of employment could not in any event constitute an objective ground within the meaning of Clause 4(1) of the Framework Agreement. ( 37 )

56.

In so far as the contested provision is linked to participation in the career system which is reserved for public officials under the rules of DFL 251/93, it should be stated, first, that the Court has already held that such a general and abstract criterion is not justified on objective grounds. ( 38 )

57.

Second, Spanish law clearly does not preclude, in general, participation by non-statutory contract staff in the career system. In Case C‑315/17 ( 39 ) the referring court stated that Ley 7/2007 del Estatuto Básico del Empleado Público (Law 7/2007 on the Basic Statute for Public Employees) of 12 April 2007 (BOE No 89 of 13 April 2007) (EBEP) permits participation in both career paths not only for established public officials but for other permanent staff. ( 40 ) Even if this inconsistent arrangement of the possibilities for participation in career systems were seen as an expression of the regulatory autonomy available to individual autonomous regions, this nevertheless indicates that the general exclusion of non-statutory staff from a career system cannot in any case be regarded as an expression of an inherent characteristic of national public service law.

58.

As regards the particularities of public service employment in Navarre, it should be noted, lastly, that by the career path under Article 14 of DFL 251/93 ‘officials may achieve promotion from one of the levels defined … to higher levels, and progression to higher grades and categories within each level’. ( 41 ) However, through the Fourth Transitional Provision of DFL 251/93, the system of grade progression was suspended indefinitely and replaced by a measure amounting to no more than the award of corresponding additional remuneration. ( 42 )

59.

It must therefore be stated as an interim conclusion that it is not possible to infer from the particularities of public service employment in Navarre, in particular from its organisation of the career system, any objective ground to justify the difference in treatment found to exist.

60.

Moreover, in so far as the contested provision is linked to the completion of a certain period of service, it should be borne in mind that, according to the Court’s settled case-law, Clause 4(1) of the Framework Agreement does not permit fixed-term workers to be excluded in a general and abstract manner from the grant of a financial benefit linked to the completion of a certain period of service if, in particular, that exclusion is not based on the specific nature of the tasks to be performed by the person concerned or the inherent characteristics of those tasks. ( 43 ) This approach is applied both to length-of-service allowances ( 44 ) and to other additional remuneration the grant of which is likewise dependent on the period of service completed. ( 45 )

61.

In the present case, too, the contested additional remuneration depends on the completion of a certain period of service, without taking into consideration, for example, the specific nature of the tasks to be performed by the person concerned or the characteristics of those tasks. In the light of the statements made above regarding the comparability of the situations, ( 46 ) it is in fact not evident in the main proceedings that the teaching activities carried out by teachers employed as public officials and by teachers employed as contract staff require different academic qualifications or experience. It is clear from the order for reference that, on the contrary, these two categories of teachers perform similar tasks and have identical duties. This is also confirmed by the fact that, according to the undisputed submissions of the applicant in the main proceedings, in the event of a subsequent appointment as an established public official, the period of service completed as a member of contract staff is taken fully into consideration retroactively for the purposes of the grant of additional remuneration for grade.

62.

Nor is the applicability of the principles developed with regard to length-of-service allowances to the contested additional remuneration for grade called into question by the fact that under Article 11 of DF 68/2009 fixed-term contract staff are entitled to a length-of-service allowance also provided for under the legislation of Navarre. According to the representative of the Regional Government of Navarre, the grant of both the length-of-service allowance and additional remuneration for grade — irrespective of their specific objectives — requires the completion of a certain period of service, which is different in each case. It is for the national legislature to assess the extent to which the completion of a certain period of service is to be rewarded twice; general doubts as to the meaningfulness of such an assessment, as were expressed, for example, by the representative of the Regional Government of Navarre in relation to contract staff, cannot in any case justify less favourable treatment of fixed-term contract staff compared with permanent public officials, especially since such doubts could apply equally to public officials.

63.

The award of the contested additional remuneration for grade is thus linked solely to the completion of a certain period of service, and not, for example, to the merit or ability of the worker in the public service. It is therefore ruled out a priori that the difference in treatment found to exist can be justified by specific factors within the meaning of the case-law cited above. ( 47 ) Such factors could, for example, stem from the need to take account of the specific nature of the tasks to be performed and the inherent characteristics of those tasks by laying down relevant requirements relating to the worker’s professional experience or ability having due regard to the principle of proportionality.

64.

Against this background, the reference to the different employment arrangements for public officials and contract staff is also mistaken. As has already been stated, ( 48 ) these different employment arrangements do not affect either the tasks actually performed or the professional duties which exist. In so far as the procedure for the selection of public officials is intended to offer a permanent guarantee of their professional performance, the merit and ability assessed in the procedure in question are only a partial indication of the subsequent performance of the person concerned. In any case, the different merit and ability of public officials and contract staff which the Regional Government of Navarre and the Spanish and Portuguese Governments infer from the different employment arrangements would have to be each reflected in the nature of the tasks performed and the requirements applicable in this regard in order to be able to justify a differentiation in the way in which the completed period of service is taken into consideration. That is not so in the present case, however.

65.

On the basis of the foregoing, I conclude that the difference in treatment existing between permanent public officials and fixed-term contract staff stemming from the fact that the latter are not entitled to the award and payment of the contested additional remuneration for grade cannot be justified on objective grounds.

66.

In the light of the above statements, I propose that the Court answer the request for a preliminary ruling from the Juzgado de lo Contencioso-Administrativo No 1 de Pamplona (Administrative Court No 1, Pamplona, Spain) as follows:

Clause 4(1) of the Framework Agreement on fixed-term work, which is annexed to Council Directive 1999/70/EC of 28 June 1999 concerning the framework agreement on fixed-term work concluded by ETUC, UNICE and CEEP, must be interpreted as precluding a national provision, such as that at issue in the main proceedings, which reserves for permanent public officials the award and payment of particular additional remuneration which is intended to correspond to grades by expressly excluding fixed-term contract staff and, in doing so, having regard solely to the periods of service completed.