This system comprises a retaining housing (22) formed by a hole intended to receive the anchoring member (2) and a retaining portion (5) arranged on the anchoring member (2)； - said retaining housing (22) is arranged in a part (4； 50) having a degree of elastic flexibility and is delimited by a continuous wall of this part (4； 50)； - the retaining housing (22), on the side of a first axial end, forms a first collar (27) forming a continuous circular projection capable of being elastically deformed by the retaining portion (5) arranged on the anchoring member (2)； the wall of said part (4； 50) delimiting the retaining housing (22) also forms, on a second axial end, a second collar (28) not able to be elastically deformed by said retaining portion (5).
