In 1974 Marie-Hélène Estienne worked with Peter Brook on the casting for Timon of Athens, and consequently joined the Centre International de Créations Théâtrales (CICT) for the creation of Ubu aux Bouffes in 1977. She was Peter Brook's assistant on La tragédie de Carmen, The Mahabharata, and collaborated to the staging of The Tempest, Impressions de Pelléas, Woza Albert!, La tragédie d'Hamlet (2000). She worked on the dramaturgy of Qui est là. With Peter Brook, she co-authored L'homme qui and Je suis un phénomène shown at the Théâtre des Bouffes du Nord. She wrote the French adaptation of Can Themba's play Le costume, and Sizwe Bansi est mort, by authors Athol Fugard, John Kani, and Winston Ntshona. In 2003 she wrote the French and English adaptations of Le Grand inquisiteur (The Grand Inquisitor), based on Dostoevsky's Brothers Karamazov. She was the author of Tierno Bokar in 2005, and of the English adaptation of Eleven and Twelve by Amadou Hampaté Ba in 2009. With Peter Brook, she co-directed Fragments, five short pieces by Beckett, and again with Peter Brook and composer Franck Krawczyk, she freely adapted Mozart and Schikaneder's Die Zauberflöte into Une flute enchantée.