Benoît Jacquot's previous film "Les Adieux à la reine" landed seven César nominations, going on to win three of the actual awards. It seems unlikely that "3 cœurs" will meet with similar success, which is a great pity as it may well be the director's finest couple of hours. While there is nothing especially original on display here, it's an immaculately assembled piece that features pitch-perfect performances from its four main actors.

Jacquot charges his namesake, Belgian star Poelvoorde, with the responsibility of carrying this emotional heavy-hitter, and the actor repays this faith by delivering a sensitive turn that's shorn of all the comedy and boorishness we've come to associate with his onscreen persona. Poelvoorde plays Marc, a Paris-based tax officer who misses the last train home while working in a provincial town near Lyon. While having a drink in a bar, he encounters Gainsbourg's inscrutable Sophie; the two walk together, form a connection, and arrange a meeting at Paris' Jardin des Tuileries. Due to a chaotic situation at work, Marc is late for the rendezvous and Sophie has left, resolving to move to America with the partner she was just about to walk out on.

Later on, and on another working trip to the town where he met Sophie, Marc meets Mastroianni's Sylvie and a relationship develops; marriage and a child duly follow. What we know long before Marc, however, is that Sylvie and Sophie are sisters. Obviously, when Marc comes to realise this and the US-based Sophie discovers who her sister is marrying, serious complications ensue. It should be noted that one of the three hearts of the title -- Marc's -- appears to be in very poor condition, and he spends much of his time seemingly just a croque-monsieur away from a heart attack; not the ideal condition, then, for taking on such a fraught emotional situation.

While the storyline is all very involving, this is essentially a character-driven piece in which the three main performers (plus Catherine Deneuve, sublime in the small role of the girls' mother) are all at the top of their game. The focus for most will be Gainsbourg and Poelvoorde, but in many ways the film belongs to Mastroianni -- always an engaging presence, here she gives what might well be her best performance. Given that for much of the story Sylvie is kept in the dark, and as such isn't afforded the same emotional peaks and troughs as her husband and sister, Mastroianni has to reach for other, more subtle means of expression to move us as her character deals with the quotidian details of being a wife and mother.

Gainsbourg and Mastrioanni, the offspring of four huge stars, are oddly believable as sisters and even manage to convince when it comes to depicting the extremely close bond that exists between Sophie and Sylvie. While much of the setup is familiar -- although Jacquot does invert the current trend by having a man torn between two women -- top class filmmaking can make us overlook the obvious in much the same way as these characters do.