People will say that the plot does not make sense.It does in the Prevertesque way.Mainly in the first part,it's all linked with absolute skill.
On a train ,a two-bit thief (Carette)tries to strip a lady from what she has on her:too bad,she's a thief herself and smarter than he is.So his wicked cousin Tancrède tells him there's a safe in a house in the neighborhood and he knows the combination.The hero takes his brats to the robbery ,pretending he's taking them to the dentist.Alas,he is caught in the act and his victim (Pierre Brasseur)blackmails him: either he kills his rich cousin Ludovic ,or he gives him away to the Police.
Ludovic (Charles Trénet's best film performance,by far)is considered the idiot of the village .Village idiot,yes,but in Prévert's way: that is to say he is happy,at once mad and sensible,leading his life without worrying about the gossips.
His house, where he puts up gypsies,a flower lady, a grinder and more is worthy of Prevert's poem "Inventaire" . And when Ludovic and his friends leave the house,because living alone (and leaving alone as well) is too hard for him,they make me think of another poem "En Sortant de L'Ecole" .
A good knowledge of French is useful because of the puns,the black humor and the poetry of the dialog.