A backshell for connecting an overall-shielded harness including shielded cables to a connector, the backshell including a sleeve having a full toothed ring, a first external area for receiving the terminations of the shielding, and a second external area for receiving the overall-shielding of the harness, the backshell further including an attachment ring having a first internal area and arranged so that it can slide over the sleeve up to an abutment position in which it covers the first external area of the sleeve so as to cover the terminations of the shielding. This backshell is designed to make a terminated shielding harness and a connection protected against EM interference between the terminated shielding harness and a connector.