European Court of Justice

The European Court of Justice (ECJ), formally the Court of Justice of the European Union (CJEU), is the judicial institution of the European Union, seated in Luxembourg. Established in 1952 under the Treaty of Paris as the court of the European Coal and Steel Community, it now operates under Article 19 of the Treaty on European Union (TEU) and Articles 251–281 of the Treaty on the Functioning of the European Union (TFEU).

The CJEU comprises two courts: the Court of Justice itself (one judge per member state, plus eleven Advocates General) and the General Court (which hears most direct actions by individuals and companies). Judges serve renewable six-year terms and are appointed by common accord of the member governments.

Its core functions include:

• Preliminary rulings (Article 267 TFEU) — national courts refer questions on EU law interpretation, ensuring uniform application.
• Infringement proceedings brought by the Commission against member states that breach EU obligations (Articles 258–260 TFEU).
• Actions for annulment of EU acts (Article 263 TFEU).
• Appeals on points of law from the General Court.

Landmark rulings have shaped the EU constitutional order. Van Gend en Loos (1963) established direct effect, allowing individuals to invoke EU law before national courts. Costa v ENEL (1964) established the primacy of EU law over conflicting national law. Cassis de Dijon (1979) underpinned the principle of mutual recognition in the single market. More recently, Schrems I (2015) and Schrems II (2020) invalidated EU–US data transfer frameworks on fundamental rights grounds.

The ECJ should not be confused with the European Court of Human Rights (ECtHR) in Strasbourg, which is a Council of Europe body interpreting the European Convention on Human Rights and is not an EU institution.