Abstract: An indicator unit for a motor vehicle, in particular a so-called complementary rear stop light displaying a narrow strip of light, has a plurality of light sources aligned with each other in an elongate narrow housing. Each light source emits light in a given emission field. The unit includes optical means for redirecting the light emitted by the sources in a general emission direction, and an optic having optical elements for diffusing the output light of the unit. The redirecting means comprise lenses focussed in the vicinity of the respective light sources and directly exposed to the radiation emitted by the respective sources in a central part of their emission field, together with a cylindrical mirror which reflects towards the lenses the light emitted by the sources in at least an edge portion of their emission field.