The French thriller "Garde a Vue" has the atmospherics of film noir: the rain, the dark and the pervasive feeling that nothing good can happen.

Raindrops slither down the windows of the police headquarters. Despite the downpour, a New Year's Eve party goes on across the street. Upstairs, behind the windows of the police inspector's office, a psychological drama unfolds until dawn.

Jerome Martinaud, a prominent lawyer in a small town, is called into headquarters as a witness. He has discovered the body of an eight-year-old girl who has been raped and strangled.

As questions are met with inadequate answers, he becomes the suspect. Did he kill the girl and another who'd been found eight days before? When Inspector Gallien puts Martinaud under preventive detention, or garde a vue, Martinaud comes slowly apart. Trapped and squirming, he clearly is guilty of something.

Michel Serrault, who played the drag queen Albin in "La Cage aux Folles," is remarkable as Martinaud, the ordinary man shifting uncomfortably in his chair. When he is arrogant, we feel contempt for him; but he can inspire sympathy, too, as he tries to maintain his dignity.

Craggy Lino Ventura plays Inspector Gallien: big, tough, and, apparently, fair. That he acts more like an internist recording his patient's medical history than an interrogator just enhances the image.

When Martinaud's wife (Romy Schneider) appears two-thirds through the movie, it's to present evidence against her husband. She married Martinaud for his money and got more than she'd bargained for. She is cold and restrained yet believable.

The movie is spare -- confined mainly to one room at police headuarters, with brief flashes of the scenes of the crimes and the long upstairs hallway in the suspect's home, symbolic of the barrenness of his marriage.

This spareness of setting embodies the movie's strength and its weakness. The single room creates a feeling of no exit. Isolating the characters in the room proves effective, too -- up to a point. But focusing too long on the nuances of furrowed brows and pursed lips becomes tedious.

Perhaps the ennui that sets in about mid-movie reflects a human annoyance at endless interrogation. Even the dialogue acknowledges the dead calm of the doldrums, when Inspector Gallien says of the inquiry, "We're tired. Let's speed it up." How about a little chase scene?

The ending is a double-barreled surprise, not an ending that sews the last stitch in the psychological cloth. It's not a cop-out, but it's not an "ah, yes!" ending, either. What is strong about "Garde a Vue" are the characterizations. What's weak is that we have to rely on them so much.

GARDE A VUE -- At the Key.