Merci! So the "en Congrès" means "in congress" and not "in Congress," then.
Yes.
In fact it's in congress in Versailles (Versailles being the place where the National Assembly and the Senate gather themselves to form the "French Congress").
I'm not a legal expert, but, as I understand it, it means a criminal or civil investigation. In France, it is usually carried out by the juge d'instruction, although the government has controversially decided to eliminate that office. Hopefully someone who knows more about the French legal system can help verify this.
To complete it and to give the meaning of it: in France the instruction in the context of Justice, or furthermore of Right, is to refer to the constitution, the making, the building, of a file. But in that sense it is mainly used for a context of justice, by making an instruction, the judge of instruction will gather all the elements about an affair.
