Ferdinand Griffon (Jean-Paul Belmondo) is unhappily married and has been recently fired from his job at a TV broadcasting company. After attending a mindless party full of shallow discussions in Paris, he feels a need to escape and decides to run away with his baby-sitter, an ex-girlfriend, Marianne Renoir (Anna Karina), leaving his wife and children and bourgeois lifestyle. Following Marianne into her apartment and finding a corpse, Ferdinand soon discovers that Marianne is being chased by Algerian gangsters, two of whom they barely escape. Ferdinand (whom Marianne decides to call Pierrot, much to his annoyance) and Marianne go on a traveling crime spree from Paris to the Mediterranean Sea in the dead man's car. They lead an unorthodox life, always on the run. Settling down in the French Riviera after having burnt the dead man's car (full of money) and sunk a second car into the Mediterranean Sea, their relationship becomes strained. Ferdinand ends up reading books, philosophising and writing in his diary. Marianne becomes bored of the Robert Louis Stevenson-ness of their living situation and insists they return to town, where in a night-club they meet one of their pursuers. The gangsters waterboard Ferdinand and depart. In the confusion, Marianne and Ferdinand are separated, with Marianne traveling in search of Ferdinand and Ferdinand settling in Toulon. After their eventual reunion, Marianne uses Ferdinand to get a suitcase full of money before running away with her real boyfriend, to whom she had previously referred as her brother. Pierrot shoots Marianne and her boyfriend, and, in the climactic scene, paints his face blue and decides to blow himself up by tying sticks of red and yellow dynamite to his head. Regretting his decision at the last second, he tries to extinguish the fuse, but he is blinded by the dynamite and is blown up.
Source : Wikipedia