The Court of Justice of the European Union (CJEU) is the judicial authority of the EU. It ensures compliance with the law in the interpretation and implementation of the EU Treaties. 

As part of its mission, the Court : 

• evaluates the legality of the EU institutions’ acts; 
• ensures that Member States comply with the obligations under the Treaties;
• interprets the EU law upon request of national courts. 

The CJEU is seated in Luxembourg and is composed of two judicial bodies: 

• The Court of Justice; 
• The General Court. 

A third body, the European Union Civil Service Tribunal, established in 2004, ceased to operate in 2016 after its jurisdiction was transferred to the General Court in the context of the reform of the EU’s judicial structure.

The CJEU is the sole multilingual judicial body in the world, since all Member States’ languages can be used as the language of procedure. The multilingual regime ensures both communication with the involved parties in their own official language and dissemination of the Court’s jurisprudence in all Member States.

The Court of Justice is made up of 28 judges plus 11 advocates general; the General Court is composed of 2 judges for each Member State . Both the judges and advocates-general are appointed jointly by national governments for a renewable six-year term. They are nominated among "persons whose independence is beyond doubt and who possess the qualifications required for appointment to the highest judicial offices in their respective countries or who are jurisconsults of recognised competence". The Court of Justice’s members choose their President  for a renewable term of three years.