A controlled-luminance lighting device comprising a fluorescent light source of a linear type (5), which extends longitudinally between a reflector (1) that is formed by an elongated body having a curved surface, and a set of transverse fins (3), which are set at a distance apart from one another and which define a grill for directional control of the light emitted by the light source (5). The reflector (1) defines, together with the transverse fins (3), a plurality of elements (2) set alongside one another of a generally parabolic shape.