Jeanne-Claude was born on the same day as Christo, (13 June 1935) in Casablanca, French Morocco (now Morocco). 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. During World War II, Jeanne-Claude lived with her father's family while her mother fought in the French Resistance. Returning after the war ended in 1945, Précilda found Jeanne-Claude emotionally disturbed and malnourished.

In 1946, Précilda married the influential General Jacques de Guillebon. The family lived in Paris from 1945 to 1952, relocating to Tunisia in 1952 and returning to Paris in 1957.

Biographical information from Wikipedia