Procedure
The ECJ has its own Rules of Procedure. As a rule the Court’s procedure includes a written phase and an oral phase. The proceedings are in a language chosen by the applicant. The working language of the Court, however, including the language in which the judges deliberate and the language in which preliminary reports and judgments are drafted is French. This makes the ECJ, along with the General Court of the European Union, the only international court where French is the sole working language. The Advocates-General, by contrast, may work and draft their opinions in any official language, as they do not take part in any deliberations. These opinions are then translated into French for the benefit of the judges and their deliberations.
Read more about this topic: European Court Of Justice