Installing a caravan or mobile home in your garden is not trivial. French law regulates this practice.
Obligations vary mainly depending on the duration of installation of the equipment. For caravans, if the installation lasts less than three months per year, then it is possible to install it on your land without requesting planning permission. For mobile homes, the law is more restrictive. Having a leisure mobile home is not authorized. However, it's possible to have one on your property if it is your main residence.