La vie est un long fleuve tranquille

« Ces deux familles n'auraient jamais du se rencontrer ! »

Two babies are switched at birth. When the mistake is discovered 12 years later, it leads to complications in the lives of both families. One family is affluent, with dutiful and (apparently) contented children. The other family is poor, with rambunctious (even delinquent) children, often hungry, but with lots of laughter in the house.