Case C‑350/24

HJ

v

Crédit agricole Corporate & Investment Bank

(Request for a preliminary ruling from the Cour de cassation (France))

Judgment of the Court (Grand Chamber) of 19 May 2026

(Reference for a preliminary ruling – Article 50 TEU – Article 288 TFEU – Agreement on the withdrawal of the United Kingdom of Great Britain and Northern Ireland from the European Union and the European Atomic Energy Community – Court of a Member State seised before the end of the transition period provided for in that agreement – Application by the courts of the forum of the law of another State – United Kingdom legislation transposing a directive – Directive 2006/54/EC – Applicability of EU law – Principle of mutual trust – Principle that national law must be interpreted in conformity with EU law)

1. Social policy – Male and female workers – Access to employment and working conditions – Equal treatment – Directive 2006/54 – Scope – Withdrawal of the United Kingdom from the European Union – Withdrawal Agreement intended to ensure the principle of legal certainty – Dispute relating to alleged acts of discrimination on grounds of sex in the context of an employment contract governed by United Kingdom law – Acts which occurred before the date of the end of the transition period provided for in the Withdrawal Agreement – Dispute pending before a court of a Member State after that date – Applicability of EU law to such a dispute

   (Art. 50(3) TEU; Agreement on the withdrawal of the United Kingdom from the European Union and Euratom, Arts 126 and 127; European Parliament and Council Regulation No 2006/54, Art. 19)

   (see paragraphs 57, 60-65, 70-73, operative part 1)

2. Acts of the institutions – Directives – Implementation by Member States – Need to ensure that directives are effective – Obligations of national courts – Obligation of conforming interpretation – Interpretation and application by a court of a Member State of the law of another Member State implementing a directive – Included – Limits – Observance of general principles of law – Interpretation of national law contra legem

   (Art. 288, third para., TFEU; European Parliament and Council Directive 2006/54, Art. 19)

   (see paragraphs 80-84, 88-90, 93-95, 100, operative part 2)

Résumé

Hearing a request for a preliminary ruling from the Cour de cassation (Court of Cassation, France), the Court of Justice, sitting as the Grand Chamber, rules on the novel question of the scope of the principle that national law must be interpreted in conformity with EU law where a court of a Member State is seised of a dispute in which the applicable law is that of a State which, at the time when the dispute arose and the court was seised, was a member of the European Union but which withdrew from it before that court gave a ruling.

In 2007, the appellant in the main proceedings was employed under a contract of employment governed by United Kingdom law. In 2013, taking the view that she had suffered discrimination on grounds of her sex and psychological harassment, she brought an action before a conseil de prud’hommes (Labour Tribunal, France) seeking payment of various sums, inter alia by way of compensation.

After her claims were dismissed at first instance and on appeal, the appellant brought an appeal before the Cour de cassation (Court of Cassation), in which she claims, inter alia, that the appellate court ruled on the basis of an interpretation of the applicable United Kingdom law contrary to Article 19(1) of Directive 2006/54. ( 1 )

It was in the particular context of that dispute which was pending on the date of the end of the transition period provided for in the Withdrawal Agreement ( 2 ) and relating to alleged acts of discrimination which occurred before that date in the context of the performance of an employment contract governed by United Kingdom law that that court decided to refer the matter to the Court of Justice. It seeks to ascertain, first, whether the applicability of Article 19 of Directive 2006/54, which lays down the rules relating to the burden of proof in the context of the implementation of the principle of equal treatment of men and women in matters of employment, has been called into question by Article 50(3) TEU and the Withdrawal Agreement. Second, that court is uncertain whether the principle that national law must be interpreted in conformity with EU law, which is binding on a court of a Member State, applies where that court must apply the law of another Member State.

Findings of the Court

In the first place, the Court observes that the United Kingdom has not been a Member State since 1 February 2020, ( 3 ) but that, in order to ensure an orderly withdrawal, the Withdrawal Agreement expressly provides for the extension of the application of EU law to that State, with a few exceptions, until 31 December 2020, the date of the end of the transition period.

Although the Withdrawal Agreement does not contain any general provision governing the applicability of EU law beyond that date, the Court notes that that agreement expressly recognises that EU law may apply to certain contractual relationships and to certain disputes which arose before the end of the transition period and which are still pending after that period. Moreover, Article 50(3) TEU does not in any way indicate that EU law is no longer applicable to pre-existing situations in a State after its withdrawal from the European Union.

Thus, according to the Court, it follows from the general scheme of the Withdrawal Agreement that the parties to that agreement wished to preserve the stability of legal situations existing before the end of the transition period in accordance with the principle of legal certainty, compliance with which that agreement seeks to ensure. In view of the fundamental importance of that principle, the Court considers that it cannot, in the absence of an express provision in the Treaties and in the Withdrawal Agreement, be considered that the European Union and the United Kingdom have agreed to terminate retroactively the application of EU law to a dispute which was pending on the date of the end of the transition period and relates to alleged acts of discrimination which occurred before that date in the context of an employment contract governed by United Kingdom law.

As regards more specifically Article 19(1) of Directive 2006/54, the Court states that that provision lay downs not a mere procedural rule but a substantive legal rule governing the employment relationship created by a contract concluded before the end of the transition period, with the result that that rule continues to apply, even after the end of that period, to disputes concerning that relationship. An interpretation to the contrary would result in a serious limitation of the scope of the principle of legal certainty and of the effective implementation of the principle of equal treatment which is at the heart of Directive 2006/54.

Consequently, the Court holds that Article 50(3) TEU, read in conjunction with Articles 126 and 127 of the Withdrawal Agreement, must be interpreted as meaning that that agreement has not called into question the applicability of Article 19 of Directive 2006/54 to a dispute such as that at issue in the main proceedings.

In the second place, the Court recalls that when national courts apply their domestic law, they are bound to interpret it, so far as possible, in the light of the wording and the purpose of the directive implemented by that law in order to achieve the result sought by the directive and consequently in order to comply with the third paragraph of Article 288 TFEU.

The application of the principle that national law must be interpreted in conformity with EU law contributes to observance of the principle of mutual trust between the Member States, which requires each of them, save in exceptional circumstances, to consider the other Member States to be complying with EU law. Thus, where national courts apply the law of another Member State, they endeavour to investigate the content of that law and the interpretation given to it by the courts of that State. They must apply national law in conformity with EU law and, where appropriate, disapply any provision of that national law which cannot be applied in conformity with EU law.

The Court specifies that the review carried out by a court hearing an appeal on a point of law in response to a plea alleging that a lower court or tribunal has interpreted the law of another Member State in breach of a directive cannot be limited solely on the ground that, as a general rule, that court treats foreign law as a factual matter. That review must relate to whether the lower court has complied with the obligation to interpret in conformity with the result prescribed by the directive which exists irrespective of whether the law to be interpreted is that of the forum or of another Member State.

Accordingly, the Court holds that Article 288 TFEU must be interpreted as meaning that, where a court of a Member State interprets and applies the legislation of another Member State which implements a directive, it is required, as it is when interpreting and applying its own law, to observe the principle that national law must be interpreted in conformity with EU law.

( 1 ) Directive 2006/54/EC of the European Parliament and of the Council of 5 July 2006 on the implementation of the principle of equal opportunities and equal treatment of men and women in matters of employment and occupation (OJ 2006 L 204, p. 23).

( 2 ) Agreement on the withdrawal of the United Kingdom of Great Britain and Northern Ireland from the European Union and the European Atomic Energy Community (OJ 2020 L 29, p. 7; ‘the Withdrawal Agreement’).

( 3 ) Under Article 50(3) TEU, the Treaties ceased to apply to the United Kingdom on the date on which the Withdrawal Agreement entered into force, namely on 1 February 2020.