a motor vehicle seat including a seat part and a foldable seatback including a rear face including a tray , the seatback configured to be folded onto the seat part to bring the rear face thereof into a substantially horizontal position . the tray is affixed against the rear face of the seatback and is held against the face by a locking mechanism including an actuating member , and a pressure exerted on the actuating member releases the tray such that the tray can be removed from the seatback .