Living in a condominium means, above all, accepting to share the ownership of a building, new rules, a new lifestyle, and above all, duties and responsibilities. Becoming a co-owner therefore implies acting not for oneself, but on behalf of a group of co-owners, most often united in a syndicate of co-owners. The overall management of each lot most often requires the appointment of a co-ownership trustee responsible for financial, accounting and legal management, as well as many other day-to-day issues. In this report we will focus solely on professional trustees who manage co-ownerships. This leads us to ask the following question: is there complete freedom when concluding a management contract? Indeed, many abuses occur, whether in the negotiation of contracts, the insertion of abusive clauses (fees which continue to increase), and many others, which we will examine.