She was born into a Jewish family in Tunis and attended the private Catholic school Notre-Dame de Sion there.

When French president Charles De Gaulle removed Barrault from the directorship of the Odéon-Théâtre de l'Europe because of his support for the student revolt of 1968, Benmussa was put in charge of theatrical works at publisher Éditions Gallimard.

Her play was translated into English and performed in London and New York City.

She also developed plays from the works of Henry James, Sigmund Freud, Virginia Woolf, Tolstoy, Nathalie Sarraute, Edith Wharton, Gertrude Stein and others.

[1] She published several books and produced a documentary film Regards sur Nathalie Sarraute in 1978[2] She received an Obie Award and the Prix de la révélation théâtrale de l'année du Syndicat de la critique [fr].