Trintignant was born in Nice. She is the sister of late actors Christian Marquand and Serge Marquand. In 1960, she married French actor Jean-Louis Trintignant, who had already starred in several of her early films. The couple had three children: a daughter, actress Marie Trintignant; another daughter, Pauline; and a son, actor and screenwriter Vincent Trintignant-Corneau. They separated in 1976. Following their split, Trintignant started a relationship with French director Alain Corneau, who later adopted her children Marie and Vincent. Trintignant and Corneau lived together for 37 years until his death in 2010.