This fastening system (89), comprises a bushing (27), comprising a main body (33), having an essentially cylindrical shape which defines a main axis (X27) of said bushing, an external collar (39), provided at a proximal axial end (37) of the main body (33), a bore (49), provided through the external collar and the main body, along the main axis, and at least one clamping wing (53), which is provided within a lateral aperture (55) of the main body and is elastically orientable between an outward orientation and an inward orientation relative to the main body, the fastening system comprising a plug (29), which is shaped to be inserted, at least partially, into the bore along the main axis through the external collar, wherein the plug (29) is shaped to force the clamping wing (53) into the outward orientation when said plug is inserted in the bore (49).