Abstract: Fastener (1) includes a head (2) and a body (3). The head (2) has a transverse stop (5) able to bear on the first piece (23). The body (3) has a first spacer (10) and a second spacer (11), coaxial and disposed in line with each other in an axial direction. The first spacer (10), adjacent to the head (2), has a diameter greater than that of the second spacer (11) which extends starting from the first spacer (10), on the opposite side from the head (2). Each of the spacers (10, 11) has at least one lug (13; 18).