There, María attended the Victor Duruy school, where she learned French and was befriended by a teacher and his Spanish wife, who inspired her to go into the theatre.

There, over the course of the next three years, she appeared in several plays including, Deirdre of the Sorrows by J. M. Synge, The Master Builder by Ibsen, Le Malentendu (The Misunderstanding) by Albert Camus (with whom she would later have a passionate affair), and an important premiere, Fédérico, after Prosper Mérimée, with Gérard Philipe.

Casares took French nationality in 1975 and three years later married André Schlesser, an actor known professionally as Dade, who had been her longtime companion and theatrical co-star.

[3][4][5][6][7] The couple never married, but their extensive correspondence, first published in France in late 2017, lasted from 1944, with a five-year break to 1949, when they again had a chance meeting when their passion was rekindled until the end of Camus' life.

[12][13] The actress died of colon cancer at her country house, Château de La Vergne, in the village of Alloue in Poitou-Charentes, on the day after her 74th birthday.