You may rent your apartment from an individual or an agency (« régie immobilière »)
It is important to make an initial survey (called « un état des lieux d’entrée ») , an agreement signed by you and the proprietor or agency. This will save you trouble when you leave the apartment.
The duration of a lease for rented accomodation is normally one year, renewable by tacit agreement.
More and more frequently, a rent guarantee deposit is required. It can be paid by bank transfer or by warranty. The sum required is the equivalent, maximum, of 3 months rent and remains blocked until the lease is terminated.