Gilles Mimouni's L'Appartement (1996)

L'Appartement is a film in two parts – the past and the present. At the beginning Max (Vincent Cassel) literally bumps into Lucien (Jean-Philippe Ecoffey), his friend he's not seen for a few years, in Montmartre, and since then he's married Muriel (Sandrine Kiberlain). He'll be in touch wih Lucien in five days, as he has to go to Tokyo for four days. But he delays his flight because he sees Lisa (Monica Bellucci), a young woman he was madly in love with earlier (one of the many flashbacks tells us) but she just appears to have walked out on him, although he's still in love with her.

So Max laboriously tracks Lisa down, but in what he thinks is her apartment he meets Alice (who also calls herself Lisa) and (with very little persuasion from her) soon falls for her too. Later, though, he discovers that Alice has been in love with him all the time, been tracing his steps far more than Max has lately been tracing Lisa's, has all her love and movements written in a diary, and although she's Lucien's lover when she eventually meets Max, she's only a lukewarm one.

But Max only finds this out at the last minute, about the time Lisa has been blown up in the apartment, and although he meets Alice at the airport, he also meets Muriel too, so what can he do? Lucien, who is thrown back by the blast of the apartment exploding, is loved by no woman it seems, although Max is loved by three. Confusing? No, not really, although this makes for a very enthralling film.