In “Petite Maman,” Céline Sciamma’s follow-up to her critically lauded “Portrait of a Lady on Fire,” 8-year-old Nelly (Joséphine Sanz) has just lost her beloved grandmother and is helping her parents clean out her mother’s childhood home. She explores the house and the surrounding woods where her mom, Marion, used to play and built the treehouse she’s heard so much about. While walking in those woods, Nelly meets another 8-year-old girl who looks startlingly like her. She’s building a treehouse, and her name is Marion (Gabrielle Sanz, Joséphine’s twin sister) — Nelly’s “petite maman.” Deadline’s Todd McCarthy writes: “The two most mature and emotionally insightful 8-year-old girls you’ve ever encountered in your life are the subjects of ‘Petite Maman.’ Magnetically attentive to the serious ‘things of life,’ as the French put it, Céline Sciamma’s 72-minute study of an intense brief friendship between two girls of extraordinary similar looks prioritizes insight and emotional awareness over any artificial plot constructs. The result is a piercingly satisfying chamber drama with a lovely intimate feel. In all events, this is an arrestingly original and alive creation that offers acute observations and unexpected grace notes.”