The Pharmacist (2003)

In appearance, Yan Lazarrec is a peaceful for man. An ecological pharmacist, he relieves humanity with his potions and fights to protect it in the long haul against the polluters who are destroying it. François Barrier, a staunch environmentalist, but a cop above anything else, is investigating a series of murders. The two men meet and become friends at an ecological conference. They don't yet know they'll become enemies.