A lighting module for illumination and/or signalling in a motor vehicle includes a base supporting, on a first face, at least one light source that emits light rays, most of which extend along an optical axis perpendicular or substantially perpendicular to the first face, and a primary optical device including a receiving portion opposite at least one portion of the light source and an output face opposite the receiving portion. The lighting module has at least one arm projecting from the first face of the base and holding the primary optical device at a retaining zone positioned between the receiving portion and the output face of the primary optical device.