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The principle of cooperation between the institutions

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The principle of cooperation between the institutions

Cooperation between the institutions is essential to the proper functioning of the European Union. Indeed, the Court of Justice has recognised the duty of sincere cooperation as a general principle of Community law. While sincere cooperation is not explicitly mentioned in the Treaties, this does not affect its status as a requirement with which all Member States and European institutions must comply.


The principle of "sincere cooperation" stems from Article 4 of the Treaty on European Union (TEU) in the context of relations between the European Union (EU) and Member States and Article 13 of the TEU in the context of relations between the EU institutions.

In substance, this Article states that the Member States must take all appropriate measures to fulfil their obligations arising out of the Treaty and do nothing detrimental to the proper functioning of the European Union.

Cooperation between the Member States and the EU institutions

Member States have a duty of sincere cooperation with the EU institutions. Accordingly, they are asked to support EU activities and not to hinder their proper functioning. This involves, for example:

  • punishing infringements of EU law as strictly as infringements of national law;
  • cooperating with the Commission in procedures linked to the monitoring of compliance with EU law, e.g. by sending the documents required in accordance with the rules;
  • making good any damage caused by infringements of EU law;
  • not unnecessarily hindering the internal operation of the European institutions (for example, by taxing reimbursements of the transport costs of MEPs travelling to Brussels and Strasbourg);
  • cooperating with the Commission in the event of inaction on the part of the Council, so as to enable the EU to fulfil its responsibilities (for example, to fulfil urgent needs concerning the conservation of certain fish stocks).

Article 4 of the TEU invites the EU and the Member States to respect and assist each other in carrying out tasks which flow from the Treaties.

Cooperation between the institutions

In accordance with Article 13 of the TEU, the EU institutions are required to comply with the principle of mutual “sincere cooperation”. They are:

  • the European Parliament;
  • the European Council;
  • the Council;
  • the European Commission;
  • the Court of Justice of the European Union;
  • the European Central Bank;
  • the Court of Auditors;

This principle is applicable in accordance with the case law of the Court of Justice of the EU.

The principle of interinstitutional cooperation can also be found in Article 249 of the Treaty on the Functioning of the European Union (TFEU), which lays down that the Council and the Commission must consult each other and settle by common accord their methods of cooperation.

Interinstitutional cooperation takes place in various ways, including:

  • exchanges of letters between the Council and the Commission;
  • interinstitutional agreements;
  • joint declarations of the three institutions.

Last updated: 11.08.2010