Heartbreaker is a French romantic comedy film released in 2010, directed by Pascal Chaumeil and starring Romain Duris, Vanessa Paradis, and Julie Ferrier. The story follows Alex (Romain Duris) and his sister Mélanie (Julie Ferrier), who run a business called "The Breaker Upperers", which specializes in breaking up unhappy relationships.
Their latest client is a wealthy businessman named Marc (Andrew Lincoln), who wants to prevent his daughter Juliette (Vanessa Paradis) from marrying her fiancé, Jonathan (Andrew Buckley), whom he believes is not good enough for her. Alex and Mélanie accept the challenge, but they only have one week to do it.
The first step is to get close to Juliette and learn more about her relationship with Jonathan. Alex poses as an illegal immigrant from Yugoslavia and becomes Juliette's dance partner, while Mélanie pretends to be a lesbian and becomes her roommate. Soon, Alex starts to develop feelings for Juliette, despite knowing that he should stay professional.
As the wedding day approaches, Alex and Mélanie try a series of ridiculous schemes to create doubt and discord between Juliette and Jonathan, including hiring a fake ex-girlfriend of Jonathan, staging a fake wedding proposal, and even faking Alex's death. However, all their efforts seem to bring Juliette and Jonathan closer together, and Alex realizes that he has fallen in love with her.
In the end, Alex admits his feelings to Juliette, but she tells him that she loves Jonathan and wants to marry him. Marc accepts their relationship and gives them his blessing, and Alex decides to quit his job as a breaker upperer and pursue his dream of becoming a wine grower. The movie ends with Juliette and Jonathan's wedding, and Alex and Mélanie starting a new business venture together.