A lighting module for a motor vehicle headlight, designed to give a beam with cutoff, and comprising at least one light source, a collecting mirror, a bender having a reflective surface and a cutoff edge, a return mirror, for producing towards the front the output beam with cutoff the surfaces of the collecting mirror, of the bend and of the return mirror being conjugate surfaces such that the collecting mirror converts a spherical wave issuing from the center of the source into a wave surface reducing to a two-dimensional curve, convex towards the front, the cutoff edge of the bender is merged with this curve, the return mirror converts the above wave surface into at least one cylindrical wave surface of vertical axis having as its cross-section a curve.