Article 692-2 of the French Code of civil procedure
When, in application of the present code, the clerk’s office summons the parties to the hearing by registered letter with acknowledgement of receipt, the parties or some of them may, upon the judge’s mention in the file, be notified of this hearing date by simple letter. If a party notified by simple letter does not appear at the hearing or has not been represented at it, it shall be summoned…