Daughter of director Jacques Doillon and actress Jane Birkin, half-sister of Charlotte Gainsbourg, half-sister in law of Yvan Attal, Lou was born in the French movie industry. She had a rebellious adolescence, and started her acting career as her mother's daughter in Kung-fu master! (1988). Then, her father offered her her first great role in a movie, it was Trop (peu) d'amour (1998), and she also played in Mauvaises fréquentations (1999). She became a model because of her atypical beauty and is now a star in the French and European movie industry.