Abstract: The housing comprises an actuating lever (8) articulated about a transversal spindle (13), and a mechanism (16), controlled by the lever, capable of driving, in opposite direction, two rods (17, 18); each rod is provided, at its end farthest away from the housing, with a bolt, in order to bring about a locking at an upper point and a lower point, respectively. The actuating lever (8) comprises a unilateral thrust organ (19) capable of co-operating with one or two complementary abutments (21, 22) provided for on a driving organ (23) of the mechanism (16), whereby the lever (8) may be tilted from one position into another, to co-operate with the appropriate complementary abutment (21, 22), in order to selectively allow the fitting onto a "right-hand" or "left-hand" door.