A fastening clip device comprising arms of different length pivoted together about a transverse pin on one and the other side thereof, and elastic means which maintain two facing portions of said arms spaced apart, one end of one of said arms being bent substantially to U-shape to retain the end of the other arm against the action of said elastic means, characterized in that the arm of smaller length comprises two apertures positioned on one and the other side of the pin about which the two arms are pivoted, and by comprising a flexible puller which passes through said apertures, extends between the pin and the arm of greater length, and is fixed to the curved portion of said arm.