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