A connector for a multipolar lead having a substantially cylindrical cavity that contains a stack (200) of alternating annular electrical contact elements (210) and annular isolation elements (220). The isolation elements (220) comprise an annular rigid sleeve and an annular flexible seal disposed against an annular face in an interior region of the rigid sleeve. The flexible seal extends axially from one lateral side of the rigid sleeve to the other in the interior region of the rigid sleeve. The sleeve and the seal include are immobilized relatively to each other in the axial direction by use of mating surface profiles respectively defined on an inner annular side of the sleeve and on an outer annular side of the flexible seal. In addition, each lateral side of the flexible seal is projecting with respect to the corresponding lateral sides of the rigid sleeve.