Abstract: The invention relates to a control system, comprising—a first assembly (14), fitted to the cabin (12) of the heavy goods vehicle (11) with at least one control cable, one end of which is designed to be fitted to a gear lever (24) of the heavy goods vehicle, the other end being connected to a operating means such as to move the operating means between first and second positions on a movement of the gear lever (24) by a user, a second assembly (31) mounted on the chassis (13) of the heavy goods vehicle (11) and comprising at least one control cable, one end of which is connected to an operating means and the other end of which is designed to be connected to a gearbox (40) of the heavy goods vehicle such as to bring about a change of gear ratio on a movement of the operating means between the first and second positions, the two operating means cooperating with each other in the operating position of the cabin such that a movement of the operating means of the first assembly (14) brings about a movement of the op