The invention relates to a motor vehicle driver assistance system (100) comprising at least one detection module (101) and a cleaning device (120), the detection module (101) comprising at least one driver assistance sensor (110, 130) and at least a protective window (140) closing the detection module (101) and protecting the at least one driver assistance sensor (110, 130), the cleaning device (120) being configured to clean the protective window (140) and the cleaning device (120) comprising at least one wiper (121) in contact with the protective window (140) and able to move in a rectilinear main direction (D).