A female connector (1) configured to receive a male connector (2), having an annular exterior retaining rim (24), the female connector including a body (10), and a transverse slide (4) forming a housing, the housing (4) including two lateral grooves (41,42), the female connector including a separate deformable locking ring (3) capable of being inserted in the housing and of locking the male connector in the coupling position, the locking ring including two first concave arched portions (31), as viewed from the axis, and two second arched portions (32), with inverse curvature, i.e. convex when viewed from the axis, the second arched portions being capable of flexing towards the exterior during insertion of the male connector and capable of abutting on the external annular retaining rim and preventing withdrawal of the male connector, whereby after locking of the male connector in the female connector a definitive locking is obtained.
