Albert Topaze, sincere schoolteacher addicted to "rote" morality, works at a private school run by supremely money-grubbing M. Muche, whose daughter, also a teacher, makes cynical use of the knowledge that Topaze loves her. Alas, Topaze's naive honesty brings him unjust dismissal...and makes him fair game for the "aunt" of his private pupil, really the mistress of crooked politician Regis, who needs an honest-seeming "front man." Can artful Suzy Courtois keep Topaze on the string? With steadily escalating disillusion comes moral crisis...

Topaze, un instituteur, est secrètement amoureux d'Ernestine, la fille du directeur de l'institution. Ce-dernier en apprenant la nauture des sentiments de son employé le licencie sur le champ. Topaze est alors engagé par un politicien véreux, expérience qui va le transformer du tout au tout.