Professor Poponof, an old scientist, has just discovered a truth serum. Amédée, a burglar who has been surprised in his apartment, will become the perfect guinea-pig for testing the prof's last find. And it works well. Too well in fact, for if Amédée tells the truth he tells it to everybody and in every circumstance, thus causing disasters around him.

Two hearing protection product sales reps have mixed fortunes in the exercise of their trades. They first have to face a female singer who... slams her door at them! Second they try to a influence a man by giving one of his friends'name as a reference whereas the aforementioned friend is... on the spot! As for the third client, he seems to be willing to buy one of their articles until the two salesmen realize that he is... hard of hearing!

The story of how the people of Paris cope with the strains and struggles of war, from the siege of the city by the Prussians during the Franco-Prussian War of 1871 to the invasion by the Germans in World War II.