Filling platform for the fuel tank of a motor vehicle with selective opening

The neck (1) has a funnel-type insert (2), and a flap (4) having a lock and rotated around a hinge axis (5) moved in a chamber by pivotal elements (6, 7) around axes (8, 9). The flap is released when the pivotal elements are pivoted by a filler tube (10) of a gas pump nozzle. The pivotal elements are pivoted around the axes. Locking hooks (24) are provided at a distal end of the filler tube, and the axes are spaced at a distance from each other along a transverse direction at a distance (12). The pivotal elements are stretched to each other by a spring.