For her performance in Little Girl Blue, Marion Cotillard became the first actress to be nominated for a César Award for Best Actress for a documentary film.
Carole Achache was one of four real-life characters that Marion Cotillard portrayed in 2023. The others were Cleopatra in Asterix & Obelix: The Middle Kingdom (2023), Louise of Savoy in The Inventor (2023), and Solange d'Ayen in Lee (2023).
The film was shot in chronological order. This is only the second film starring Marion Cotillard to be shot in chronological order, the first was Two Days, One Night (2014).
Marion Cotillard filmed all of her scenes in 8 days after spending only two months preparing for the film.
The film is based on the life of French writer and photographer Carole Achache, the mother of director Mona Achache. Carole did a similar thing when she wrote the 2011 book "Fille de" ("Daughter of"), about her relationship with her mother, the novelist and screenwriter Monique Lange.