The tenant cannot be held responsible for the ageing due to time passing. It is normal that the furniture leave marks in the carpet as time goes by, that the wall painting looks darker where pictures were hanged. These signs caused by the wearing effect of time are to be classified as « reasonnable deteriorations » resulting from the ordinary day-to-day use of the apartment.
A dilapidation reference grid can be helpful for a more precise evaluation during the outgoing inventory of fixtures. The lessor can refer to his/her invoices of home improvement works and miscellaneous purchases to determine how old is the carpet and the painting, and thus see if the wear and tear is normal.
Conversely, the tenant is responsable for dilapidations such as holes in the carpet, marks of stiletto heels on the parquet floor, a chip in the enamel sink, a defect in the flexible shower hose. Also in the case of interior fitting-out works such as a ceiling painted in black or an interior wall pulled down. Generally, the tenant has no right to modify the apartment unless lessor autorization. Should the case arise, the tenant is liable for the reconditioning of the apartment.

Useful information:

In some cases, the tenant gets the lessor authorization to make interior works without having to recondition. Nevertheless, as a precaution, you should always demand written agreements.

Examples of dilapidation grids

www.opac-montpellier.fr
www.opacparis.fr
www.habitationmoderne.org

Annual dilapidation rates, for reference only

Electrical appliances    20%
Hi-fi    20%
I.T.    30%
Pieces of furnitures     10%
Wall paper, interior paint    18%
Pieces of furnitures      18%
Wall-to-wall carpet      18%     
Parquet floor and tiling     4%
Plastic surfacing     11%
Interior millwork     6%
Metal work    11%
Plumbing fixtures    9%
Plombing     9%
Sanitary installations     6%
Water-heater     12%
Boiler     7%
PVC, wood shutters PVC bois     8%
Metal shutters     5%
Roller shutters     8%
Electric heaters     12%
Cast iron heaters     6%
Components for heating control (burners)     11%