Fixing device and vehicle having same

The fastening unit comprises of a fixing body (14) for fixation to the structure of a motor vehicle. A fixing head (12) is provided with a surface (22) for cooperating with a complementary fastener carried by an accessory to be fixed. The cooperating surface has a shape of revolution around a central axis. The cooperating surface is formed by an annular throat (20) arranged in the fixing head. An independent claim is also included for a vehicle.