A young woman leaves her baby on the beach, expecting the sea to wash her away. Was it coldblooded murder or the behavior of a depressed person who didn’t know what she was doing? This is the basic premise of the true-crime story at the heart of Saint Omer, a critically celebrated, often-riveting, but aesthetically frustrating French film.

Rama (Kayije Kagame) is a novelist of Senegalese extraction at work on her second book — a retelling of the Madea myth through the lens of the aforementioned crime. Rama has a white boyfriend we don’t get to know, two sisters, and a mother she resents — information delivered in naturalistic scenes with little dialogue. She travels from Paris to Saint Omer to observe the trial of the accused: Laurence Coly (Guslagie Malanda), a Senegalese student who came to France to become a philosopher but ended up the pregnant mistress of a much older white man.

The two women’s lives have obvious overlap, and the French justice system provides the ideal

structure to lay out Coly’s story, with the judge (Valérie Dréville) probing the facts of the crime in a way that elicits biographical information from Coly and the other witnesses. We hear about her uneventful childhood, her strained relationship with her parents in adulthood, and the dismissive racism she experienced from faculty advisors as she pursued her studies. We meet the unappealing father of her child and witness Coly’s composure in relating her experiences, even as she reveals her belief that dark forces had enchanted her. She doesn’t know why she killed her daughter, she says. She hopes the trial will tell her.

Saint Omer is the feature debut of Alice Diop, a French filmmaker whose parents immigrated from Senegal. She based the screenplay on the 2016 trial of Fabienne Kabou. Diop has a painterly awareness of space and how visual elements contribute to character development, such as how Rama arranges her desk in the hotel, or Coly’s tasteful hairstyle and clothing. But I struggled with her storytelling. Rama is the sole Black woman in the courtroom other than Coly, which Diop explores only through juxtaposing Rama with the white women in her courtroom compositions. Periodically, we see her reacting in the gallery or in her hotel room in the evening. The upsetting testimony causes her to think about unpleasant memories from her own childhood and inspires concern about her current life. Kagame gives Rama a regal bearing that dissolves when she gets upset. It’s an effective portrayal, but there isn’t enough meat in the script to make Rama a whole person.

Diop relies on numerous long, nearly silent scenes to convey Rama’s discomfort, but Rama is a cypher. Any emotional understanding we think we have of her can only be empathetic projection. Even her childhood memories are irritatingly devoid of content. Also left unexplored is the urge to kill one’s child, as well as the crime itself. The Madea myth, ripe with symbolic meaning, isn’t revisited once it’s exposited. This is storytelling by suggestion and assumption, rather than carefully woven narrative. I appreciate gray areas, but Diop’s purposefully oblique take — in combination with what I can only describe as pretentiously slow pacing — left me cold, despite a rich premise and great performances, especially by Malanda.

Drama, rated PG-13, 122 minutes, French with English subtitles, Center for Contemporary Arts, 2.5 chiles