Mister Mustard's Millions [600000 francs par mois]

When bored American billionaire Charles Vanel is amused by the happiness of poor railroad man Nicolas Koline, he offers him a wager: if Koline and his family can spend 20,000 francs a day (about $11,000 in current American money) for a year, then he'll give him a nice pension. The rest of the movie is about the poor man and his family's efforts to win the bet.