A headlight includes a frame defining a beam passage opening, a stationary protective cover, and a cut-off mechanism including a movable assembly and at least one actuating motor, the movable assembly including a cut-off bar provided with a cut-off blade, the cut-off bar being movable by the actuating motor between at least one closure position, in which the cut-off blade partially closes off the opening in the region of the stationary protective cover, and a retracted position, in which the cut-off blade unblocks the opening, the protective cover including at least one closure plate, the closure plate and the cut-off blade being designed to engage together to form a closure surface in the closure position.