A female coupling element includes two superposed coaxial rings, a locking ring and safety ring which are rotatably mounted about a body of the coupling element. The locking ring is axially immobilized with respect to the body while the safety ring is able to slide with respect to the locking ring and with the body. The locking ring (2) has at least one locking slot for receiving a projection of a second element inserted within the coupling element and a notch to lock the projection axially with respect to the coupling element, and the safety ring includes at least one safety slot having a notch which locks the projection circumferentially in the notch of the locking ring.