Motor vehicle with a flat bottomed collapsible seat

The automobile has an articulation device to pass the foundation/basis (31) from a utilization position to an intermediate position in which an inferior articulation axis (51) finds in the plan. A base (311) of the foundation spreads, or at very near to the plan of the inferior axis. The foundation passes from the intermediate position to an arrangement position in the accommodation (20) by rotation around the inferior axis.