Star rating: **
Dir: Nicolas Philibert

In 1835 Pierre Riviere, son of a Normandy farmer, plunged a bill hook into the heads of his mother, sister, and brother. In 1975, director Rene Allio made a movie about the murders. Now, Allio's assistant director, who was 24 at the time, has turned in a documentary about the shooting of that film. It's not pop but cinema that eats itself in Nicolas Philibert's mildly interesting tale.

Riviere's case is notable for more than the appalling violence perpetrated. After his arrest the killer penned an explanation for his crimes that stunned readers with its eloquence. Intrigued by this Gallic Raskolnikov, Allio wanted to shoot his film where the crime had happened and use local people alongside professional actors.

Philibert (Etre et Avoir) talks to those who took part in the filming, even managing to trace Claude Hebert, the young man who played the key role of Riviere and had a brief try at an acting career before moving abroad. Thirty years on, it's striking how much of an impact the experience continues to have on the small community. Some remain star-struck, others regard it as a brief outbreak of enjoyable madness. "A sad story," says one farmer's wife of Riviere's tale, "but we had a good laugh."

Though stemming from a clever idea, Philibert's documentary struggles to fill the running time. His interviews are over-long and don't reveal much beyond the commonplace, and there is endless footage of farmers at work, presumably to give a sense of the region. That's the only charitable explanation I can think of for including a horrific scene of a pig being stunned and slaughtered.

As can be said of Philibert's film as a whole, sometimes there is such a thing as too much detail.