À rebrousse-poil

The film follows two scientists who create a kindness serum that can turn even the fiercest individuals into gentle souls. Their successful test on a wild lion leads to the serum becoming mandatory across France and eventually Europe. As the serum spreads, characters such as Mrs. Durand transform from sour-tempered to nurturing, much to the delight of their loved ones.

However, the universal kindness brings about unforeseen complications. People begin to struggle with honesty in relationships, as seen with Mr. Durand's boss's lover, who fears hurting his feelings. The film presents a satirical look at the potential pitfalls of enforced kindness and the societal shifts that accompany such a change, highlighting the humor in human interactions and the unintended consequences of good intentions.