Why the european judges at the EU court deliberate in french?

Question

Why the european judges at the EU court deliberate in french?

Answer 1

Possibly because the European Court is in Brussels, Belgium?

However, there is no official language of the EU, the idea is to share ideals and cultures to make up one European identity. Translators are hired for large conferences, or people prefer to speak in English.

Answer 2

Because he know only france langues.

Answer 3

French is the official language in foreign diplomacy aside from the principal languages.