 To avenge herself, Clairette invites all of Les Halles to a ball, to which she lures Lange and Pitou by writing each a forged letter, seemingly signed by the other.At the ball Pitou and Lange are unmasked, Larivaudière is enraged, but realises he must hush matters up to save Barras from scandal.After a lively duet in which the two young women quarrel vigorously there is a general mêlée, ended by Clairette who extends a hand to her friend and declares that she truly prefers the faithful Pomponnet to the fickle Pitou.