Caisse des Dépôts is not authorised to settle disputes between parties. On this regard, Article L 518-17 of the French Monetary and Financial Code only authorises the consignment of contested amounts pursuant to a judicial ruling. Consignment is only possible therefore if it is authorised by a judge.
That said, before considering consignment as an option, you can try to find an amicable solution with your property manager, if necessary, by calling on a third party. For that, you can give conciliation a go by contacting a judicial conciliator. For judicial conciliators' contact details, get in touch with your nearest district court or your municipal hall or police station.
If the amicable solutions reached are not what you hoped for, you can ask for a fund consignment from the competent judge pending the settlement of the dispute. It is advised to call in the other party in the procedure, or your request could be rejected.
If you would like the other party to provide a service or fulfil an obligation, before considering the consignment option it would be in your interests to use the prescriptive order procedure (Article 1425-1 to 9 of the French Civil Procedure Code): the aim of this procedure is to swiftly obtain fulfilment of a contract.