Belgium
tapis-plain
Meaning
fitted carpet
Elsewhere
moquette
Explanation
France says moquette. In Belgium it is a tapis-plain, plain in the old sense of flat, a carpet that runs level to the walls.
Example
Le sol du salon est en parquet, celui des chambres en tapis-plain.
The living room floor is parquet, the bedrooms are fitted carpet.
Origin
The plain comes from the Latin planus, flat.
Source