Heartbreaker follows the charming, funny and effortlessly cool, Alex (Romain Duris), a professional Don Juan who makes a living breaking up couples with his sister MÃ©lanie (Julie Ferrier of MICMACS). Because business is slow, they go against their principles to break up only unhappy couples and agree to work for M. Van Der Bercq. Alex has only one week to stop the wealthy man's daughter Juliette (Vanessa Paradis) from marrying the man she is madly in love with. Alex is soon thrown into his own hilarious seduction "mission impossible" that risks him being caught by his ruthless personal creditors, angry exes and the beautiful and independent Juliette herself. But worst of all, will he discover to his own cost that when it comes to love, the perfect plan doesn't exist?