It wasn't supposed to be like this, but Finally Sunday!, a lightweight entertainment that followed The Last Metro's dazzling success, would be Francois Truffaut's swansong. A couple of months after it came out, he was dead.

In the style of his second film, Shoot The Pianist, it is based on an American pulp thriller (The Long Saturday Night by Charles Williams) and shot in black-and-white. Although the plot is faintly ludicrous and barely credible, Truffaut's fascination with Hitchcock is evident throughout. As a vehicle for his girlfriend Fanny Ardant, it has an affectionate ambiance and never takes itself too seriously.

One morning at dawn, out in the wetlands of Southern France, estate agent Julien Vercel (Jean-Louis Trintignant) crouches in a hide, anticipating the arrival of wild duck. After a few minutes he packs it in and sloshes through the marsh to where another man is crouching in another hide. He shoots him in the face at point blank range, returns to his car and drives off. Hardly subtle, you might think, almost comical, and events continue in a similar vein, mocking convention and poking fun at the provincial police.

Although designed in a B-movie mould, with classical film noir touches, this has the advantage of a relaxed Truffaut, a glamorous Ardant and an intense Trintignant. Rather than follow the expected route of murderer and moll on the run, the script reverses gender roles and Ardant becomes the leading player in an ever-deepening mystery. By the end five bodies bite the dust/mud/tarmac/carpet.

Ardant plays Barbara, Vercel's secretary, who volunteers to act as amateur detective to clear his name, while he hides out in the office. The man Vercel killed in the swamp was his wife's lover. When his wife ends up battered to death in her bedroom, he realises there must be more to this than meets the eye, or the wrong end of his 12-bore.

Nothing really adds up, but does that matter when everyone is having fun, exercising their mental muscles on an intricate whodunit?