Her paternal grandfather, Baron Henri de Rothschild, was a playwright and theatrical producer who wrote under the names Charles des Fontaines and André Pascal and owned Théâtre Antoine and Théâtre Pigalle.
And her father's brother, the vintner Philippe de Rothschild, wrote plays, owned theatres and produced films.
As an actress, she is best known for her role in two films by Jean-Pierre Melville, Le Silence de la mer (1949) and Les Enfants terribles (1950).
In 1950, Stéphane introduced her cousin (by marriage), Francine Weisweiller, to Jean Cocteau, whom she'd met while acting in Les Enfants terribles.
Among her production credits was Swann in Love (1984), an adaptation of the first novel in Marcel Proust's cycle Remembrance of Things Past, which starred Jeremy Irons and Ornella Muti.