A fairly decent adaptation of a good psychological thriller by Sébastien Japrisot, scripted by the author himself. The trouble with it is, the book's greatest strengths - the richly detailed provincial French setting and the vivid characterisation, resulting from a multiple first-person narrative - prove difficult to translate to the screen, at least within the constraints of a sensible running time. The movie, therefore, somehow manages to feel simultaneously watered-down and overlong. Japrisot attempts to preserve his first-person narrative in voiceover form, but he overuses this device considerably; I've nothing against voiceovers per se, but cinema should primarily be about visual storytelling, and any movie this reliant on narration must be doing something wrong!
Switching from coquettish sexiness to childlike vulnerability in the blink of an eye, Isabelle Adjani is marvellous in the lead role, but try to imagine the film without her and it begins to look very ordinary indeed. The rest of the cast are fine, though strictly two-dimensional. Jean Becker's direction is adequate but completely lacking in tension; a first-rate director - say, Claude Chabrol in his prime - would have made more of the psychosexual strangeness of the tale, and would have better disguised the fact that the nicely ironic ending hinges on a pretty indigestible coincidence. My advice: read the book; if you like it, watch this for Adjani.