Two women from similar backgrounds. A infanticide. Education, logic, witchcraft and a brutal world order. It's a toxic brew that director Alice Diop tackles in her film about one of France's most high-profile court cases, in which a woman named Laurence Coly faces charges of leaving her one-year-old daughter on the shores of the North Sea coast to let the tide take her.

Rama is a teacher and acclaimed author. Pregnant with her white husband and a poster name for successful integration, but the nightmares gossip about the difficult balancing act between different worlds. In one she wears cool blouses and lectures about Duras, in the other she keeps her pregnancy a secret from her depressed Senegalese mother in one of Paris' million program areas.

Equally impossible, Laurence Coly wobbles on the knife edge between studying Wittgenstein's logic, and asserting witchcraft from malicious relatives in Senegal in his defense. Rama is the audience member at the trial of Coly, who is unlikely to be assembled at the scrimmage. She eludes everyone by admitting to the murder but at the same time asserting her innocence. Her statement does not match the other testimony and the mystery surrounding her person thickens during the trial.

It's like she didn't even exist. Her supervisor at the university questions her interest in Wittgenstein and testifies with a wry smile that as a woman from Africa, she should have chosen something more fitting.

I should be deeply gripped by "Saint Omer"; the two women, the Medea myth, the institutional racism, motherhood, and the utterly magnetic Guslagie Malanda as Coly. But the court's lunk and the drawn-out scenes make the film even-keeled and, in a sense, undramatic. Rama's own demons are accounted for in flashbacks from childhood, but they are not felt.

I wish Diop had been more generous with the drama and let his actors bump into each other more often. Now they shine one at a time, like small islands of conflicting human action. Only once do the two women's gazes meet and then it's like time stops.