Henry Harriston is a psychoanalyst whose patients are driving him crazy by constantly leaving him messages during his off hours. On a whim he places an ad offering up his apartment for a housing swap. Béatrice Saulnier (Juliette Binoche) a Parisian dancer responds to his ad and without meeting the two switch apartments. Béatrice is impressed with Henry's high-tech apartment which is both beautiful and spacious. Henry meanwhile is horrified when he arrives in Béatrice's apartment and finds it filthy and messy.