Jeanne-Claude Denat de Guillebon () was born in Casablanca, Morocco, where her father, an army officer, was stationed. Her mother, Précilda, was 17 when she married Jeanne-Claude's father, Major Léon Denat. Précilda and Léon Denat divorced shortly after Jeanne-Claude was born, and Précilda remarried three times. Jeanne-Claude earned a baccalauréat in Latin and philosophy in 1952 from the University of Tunis. After Précilda married the General Jacques de Guillebon in 1947, the family lived in Bern (1948–1951) and Tunisia (1952–1957) before returning to Paris.