A device for rapid removal/reinstallation of a back of a seat of a vehicle, the back being attached, by at least one first strap, to a ceiling. The device includes a hanging intermediary structure and a fixed structure integral with the ceiling and retaining the structure in the use position of the seat, in which it has been brought with an upward movement, and locking the structure in the use position or unlocking it such that it is moved away from the ceiling to release the tension exerted by the first strap and allow the structure to be disengaged from the retaining unit. The back can thus be removed or reinstalled without any action on the tension setting of the strap.