A method and assembly for locking/unlocking, formed of one of several a removable module (2) and a mount plate (3). The assembly includes a support wall (4) supporting each removable module (2). The removable module (2) being provided with two lugs (5) through which an aperture passes. The lugs (5) extending out of the removable (2) so that they can be inserted into opening (7) formed in the support wall (4). This assembly is equipped with a locking/unlocking system (100) having a lever (10) extending under the support wall (4) and provided with circular eccentric cams (11) arranged with offset axial symmetry in the form of an S about a central rotation axle (20) perpendicular to the support wall (4). The lever (10) being fixed in terms of rotation on this central axle (2) at equal distances from the two openings (7).