Housing is defined from the point of view of its use. It is a unit used as a dwelling which is :
- separate, which is to say completely enclosed by walls and partitions, without communicating with another unit unless this is by means of the shared parts of the building (corridor, staircase, lobby, etc.) ;
- self-contained, which is to say with an entrance from which there is direct access to the outside or to the shared parts of the building, without having to go through another unit.
Housing is distributed in four categories: main residence, second homes, occasional housing, vacant housing.
There are dwellings with special characteristics but which are nonetheless classed as housing within the meaning assigned by INSEE: sheltered accommodation for the aged (in this case, the collective services are optional, otherwise this sheltered accommodation for the aged is collective accommodation), furnished rooms, and temporary housing (caravans, mobile homes, etc.).