Motor vehicle light system including an acquisition device for acquiring the scene in front of the vehicle, including an image sensor, a first lighting device including a light source suitable for emitting a first light beam lighting up the scene so as to increase the contrast of the images captured by the image sensor, a second lighting device including a light source emitting a second light beam performing a regulatory signalling and/or lighting function in front of the vehicle, a control unit which switches on the first lighting device when a first contrast value referred to as raw contrast C0 of the images captured by the image sensor is lower than a predefined threshold contrast Cs, the light source of the first lighting device being configured to generate modulated lighting, the modulation of which is imperceptible to the driver of the vehicle or an external observer.