L'Homme aux clés d'or.

Antoine Fournier, a language teacher at a secondary school in Lille, was disgraced by four young men he had caught stealing money from a charity collection. Dismissed from the teaching profession, Fournier found a job as a porter in a Monte Carlo palace through his wartime friend Ansaldi. A few years later, when he became the first concierge, the "man with the golden keys", chance brought him into the presence of the young men, married but as Machiavellian as ever. He won't take revenge on them, but their baser instincts will.