Article 11 of the French Code of civil procedure
The parties are obliged to cooperate with the investigative measures without prejudice to the judge drawing any consequences from an abstention or refusal. If a party holds evidence, the judge may, at the request of the other party, enjoin him to produce it, if necessary under penalty of a fine. He may, at the request of one of the parties, request or order, if necessary under the same penalty, the…