Article 849-8 of the French Code of civil procedure

If the third party encounters difficulties that prevent him from carrying out his task, or if it proves necessary to extend his mandate, he shall report the matter to the parties and to the judge.
The judge may decide to extend the time limit within which the third party must submit his report.

The third party’s report must be submitted to the court by the end of the month in which it is due.

Original in French 🇫🇷

Article 849-8

Si le tiers se heurte à des difficultés qui font obstacle à l’accomplissement de sa mission ou si une extension de celle-ci s’avère nécessaire, il en fait rapport aux parties et au juge.

Celui-ci peut, en se prononçant, proroger le délai dans lequel le tiers doit déposer son rapport.