Following a serious injury to the ankle, inoperable at the time, Cartier left England for France in 1957, and worked for 20 years as a mime with the celebrated troupes of Jacques Lecoq and Marcel Marceau, and as choreographer and movement specialist to theatre companies. At the Ecole Charles Dulin, she taught mime and movement, and then acted as assistant to Michael Cacoyannis for "Les Troyennes" at the Théâtre National Populaire, which production she later staged for the Festival d'Avignon. She also assisted Georges Wilson for his staging of "Grandeur et Décadence de la Ville de Mahagonny".