Monsieur Fluch,a minor public official wins one million on the national lottery.He buys mountains of things ,cars ,a medieval castle (to a marquis ,the eternal story of the ruined aristocrat who sells his mansion to the Nouveau Riche ) and shares ,encouraged by self-interested people who fawn on him (a good line about the folk song "Le Temps Des Cerises";in parallel romance between the new millionaire's daughter and a modest salesman.
Another tale which tells that money can't but happiness,as anyone past infancy should know.
Generally,in this kind of story ,the lottery ticket is lost and it's a treasure hunt (see Clair's "Le Million" and Becker's "Antoine et Antoinette").The Belgian movie focuses on the spendthrift side of the new millionaires