Director Nicholas Klotz's subtle suspense film Heartbeat Detector comes across like a hybrid of Heart Of Darkness and Michael Clayton, digging into the roots of a psychosis affecting a veteran corporate lackey. Mathieu Amalric plays a human resources psychologist who's assigned to visit his firm's Paris office, to assess the sanity of local manager Michael Lonsdale. Amalric has a reputation among his bosses as a master motivator, so the cover for his trip is that he's researching whether employees would enjoy a revival of the company's amateur orchestra. But really he's trying to cozy up to Lonsdale, a former member of that orchestra, to find out why his productivity has been so lousy lately.

What Amalric discovers is that the company he works for once earned money by supplying equipment to some very bad people, and Lonsdale is cracking under the pressure of keeping the secret. And the more Amalric finds out about it, the more he starts to break down too. He's especially shaken by reading the decades-old reports on his predecessors' business, written in the same kind of dry corporate-speak that he himself uses when he talks about human beings as "assets" and their work as "performance."

Klotz and regular screenwriting collaborator Elisabeth Perceval—adapting a story by François Emmanuel—keep the details of Amalric's psychological degeneration rooted in the physical. Heartbeat Detector doesn't rush its plot and doesn't rest everything on its climactic revelations; rather, Klotz and Perceval take time to observe Amalric chatting up pretty girls and dancing in nightclubs and interviewing job applicants, all as a way of examining what his class privilege buys him, before revealing what bought the privilege.

Heartbeat Detector can be a chilly film, and its attempts to find moral equivalency between the crimes of history and the injustices of modern business practices don't always pan out. But Amalric gives another in a recent string of riveting performances, and Klotz gets a lot of play out of the ironic distance between musical expression and corporate rigor. "Music doesn't tolerate hierarchy," one employee says, when trying to explain why the company orchestra disbanded. And Heartbeat Detector seems to imply that we should never trust any institution that would.