They're partially right, you're not allowed to stock any bottle of propane inside the house, nor cellar. This is due to the special properties of the gas; propane is bottled at 8 bar of pressure which is a big hazard when it explodes. But if you got a cooker equipped with the right burners you can use propane for cooking. Butane is bottled at 1.5 bar and can be stocked inside. Further for this butane, you can only stock one bottle of butane in reserve (that is not connected to your installation) inside the house.
The reference for it you'll find under "Arrêté du Ministère de l'Industrie du 2 Août 1977" and the "NF DTU 61.1" Guess the providers of gas bottles will have some instructions on their sites too.
If your installation, including that famous rubber tube which has an "ultimate date" imprinted on it, is not within these regulations your insurances will not pay out in case of a fire related to that installation