A process is for manufacturing a complex motor vehicle glazing including a glass pane, an elastomer seal and a metal insert overmolded by the elastomer seal. The process includes inserting an edge of a glass pane and a metal insert into an encapsulation mold forming a leaktight cavity around the edge of the glass pane, filling the leaktight cavity containing the edge of the glass pane and the metal insert, by injecting an encapsulation composition including a polypropylene (PP)/thermoplastic elastomer (TPE) compound in the molten state, cooling the encapsulation composition to form an elastomer seal in which the metal insert is integrated, and releasing the elastomer seal from the mold. The PP/TPE compound includes from 30% to 80% by weight of polypropylene (PP) and the metal insert is covered over its entire surface liable to come into contact with the encapsulation composition, with a polypropylene coating.