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It should be no surprise that the world’s best thrillers come from France. Their heroes are more independently minded and a touch wicked, so part of the delicious charm is to watch them struggle through an impossible situation. In fact, the best French thrillers, like Elevator to the Gallows and Tell No One, can even convert skeptics of world cinema. Directed by Frédéric Mermoud, the new thriller Moka could have the opposite effect: It is a touch too timid and uninvolving, with most of its focus on psychological drama. Its outright reluctance to generate suspense seems deliberate.

Based on a novel by Tatiana de Rosnay, Mermoud sets the action around the border between France and Switzerland in Lake Geneva. The lake itself is like a character in the film, or perhaps a Rorschach test. Depending on what the scene requires, the lake can seem picturesque, inviting, or deadly.

The film revolves around Diane (Emmanuelle Devos), a middle-aged woman whose only child was killed in a hit-and-run accident. A detective (Jean-Philippe Écoffey) helps Diane track the culprit through a deduction of witness testimony: They think the driver owns a vintage German car, in a coffee color, hence the title. Diane discovers a married couple—the sultry Marlène (Nathalie Baye) and her younger husband Michel (David Clavel)—that she suspects of wrongdoing. As she independently ingratiates herself with both of them, she internally begins deciding what punishments they deserve.

Devos and Baye are two of France’s finest actors, and they are appropriately cast for this material. Devos has dark, sharp features, her lips naturally curling into a frown, and she downplays Diane’s grief in favor of steely resolve. Diane is not a gifted improviser, and yet she finds herself in situations where she must invent one lie after another. There is little sense she could get caught, however, since everyone in Moka is overtly deferential. In more ways than one, Marlène is Diane’s opposite: She is blonde, for one thing, with a cheerful, open face. Baye does not play her as someone sinister, but instead as an intelligent, welcoming woman who can easily spot a ruse. Baye appears in far fewer scenes than Devos, and it’s to her credit that we constantly wonder what Marlène is thinking.

The plot is a long—sometimes achingly so—build toward suspense. Diane meets Vincent (Olivier Chantreau), a shifty young man who eventually supplies her with a pistol. Mermoud films them matter-of-factly, without much consideration for danger’s seductive qualities or what it means for an ordinary woman to consider violence. Its ambivalence toward Diane’s investigation makes the film a non-starter, the sort of affair that puzzles more than involves.

That is not to say, however, that Mermoud is incapable of an arresting image. There is a long, aching scene in which Diane observes a woman in the nightclub while Beethoven’s “Moonlight Sonata” plays. Moody lights and gyrating young people only heighten Diane’s pervasive melancholy, and the scene is one of the few moments where we sense her depth of feeling. The rest of Moka is practically polite in how it frames its situations. In thrillers, characters make deadly choices, compromising themselves along the way. Moka has an abundance of tact, to the point where barely anyone has an opportunity to sully themselves.

Diane is not exactly after vengeance, or justice. She simply wants the culprit to share her horrible feelings. This goal can be cinematic, and Moka nearly veers into an understated character study. Still, there is a dearth of curiosity here, so instead of a dramatic thriller, Moka is a mirthless revenge tale that defaults toward drama. When Diane finally finds peace, it is a narrative afterthought. She should have skipped straight to the coda and avoided all the awkward, morbid business of attempted murder.