A motor vehicle (1) has a front-end diffuser (7) that is open toward a ground surface, and has a device arranged in the region of the diffuser (7) and for varying the downforce of the motor vehicle in the region of a front axle of the motor vehicle. The device has an air conduit (12) with an inlet (13) in the region of a front-end positive pressure area of the motor vehicle and has an outlet (14) in the region of the diffuser (7), and has means (16) for opening and closing the air conduit (12). The device enables the downforce of the motor vehicle in the region of the front axle can be varied.