A device for controlling a device for locking a motor-vehicle gear change in a parking condition comprises a mechanical transmission (1) which connects the gear change lever (2) to a driven member (3a) movable between an operative position and an inoperative position, respectively for engagement and disengagement of the locking device. The transmission (1) is connected to the driven member through a rotatable drum (18) with a cylindrical surface (17) having a cam-track (16) cooperating with a cam-following element (15). The cam-track (16) is designed so as to cause engagement of the locking device when the transmission (1) is subjected to a pulling action or to a pushing action, depending upon the requirements.