Abstract: A hard plastic reflector (1) is mounted on a receiving member (4) by a joining assembly which comprises a first joining member (5) mounted on the receiving member and a second joining member (6) of plastic which flatly overlaps and lies on a wide side surface of a wall member (2) of the reflector. The overlapping portion of the wall member and the second joining member define overlapping openings (12, 13) or recesses in which a sleeve (16) of elastic material having an elongated fastening device (17) extending therethrough is positioned. The elongated fastening device presses axially, on the sleeve, or extends a bore in the sleeve outwardly, sufficiently so that an outer surface of the sleeve engages surfaces defining the openings and an inner surface of the sleeve engages the elongated fastening device in a compressed manner.