Currently it seems that the categories sedan, hatchback, coupé and coach are used differently by each person.

A coach is a 2 or 3-door car with an extra side window, e.g.:
http://www.imcdb.org/images/009/551.jpg
http://www.imcdb.org/images/010/256.jpg

So I think that it is not useful to have so many categories.

I suggest to remplace the current:
- sedan ("berline") = 4-door sedan, sometimes 2-door sedan and some limousines too
- hatchback ("berline à hayon") = 3 and 5-door sedan
- coupé = real coupés and some 2-door sedan

by the following:
- sedan/hatchback/coach
- coupé
OR:
- sedan/hatchback = 4 and 5-door sedan, and some 2-door sedan, depending on the cars
- coupé/coach = real coupés, 3-door hatchback, and some 2-door sedan

But since the coaches are usually quite small I think it is better to put them with the coupés, second solution then. Or we will still get some 2/3-door cars being put in coupés.

I wait for your comments