Michel Poiccard, an irresponsible sociopath and small-time thief, steals a car and impulsively murders the motorcycle policeman who pursues him. Now wanted by the authorities, he renews his relationship with Patricia Franchini, a hip American girl studying journalism at the Sorbonne, whom he had met in Nice a few weeks earlier. Before leaving Paris, he plans to collect a debt from an underworld acquaintance and expects her to accompany him on his planned getaway to Italy. Even with his face in the local papers and media, Poiccard seems oblivious to the dragnet that is slowly closing around him as he recklessly pursues his love of American movies and libidinous interest in the beautiful American.
Michel Poiccard is a Marseilles based hood, who will do whatever he needs to to get what he wants. He models his behavior after the tough guy characters portrayed by Humphrey Bogart in the movies. This behavior includes stealing money and cars wherever and whenever, lying and cheating, and using woman, who allow him to since they are attracted to his charisma. Because of his criminal activities, he works under aliases, such as László Kovács. One day while he is being chased by policemen in the French countryside while he is driving a stolen vehicle, he eventually shoots one of the policemen dead. He heads to Paris to take refuge with who he considers his girlfriend, Patricia Franchini, a twenty-year old American journalism student at the Sorbonne and an aspiring reporter with the Paris based office of the New York Herald Tribune. Having only dated casually over the last month, Patricia is unaware of Michel's criminal activities. She is concurrently dating another American journalist. Michel, who is trying to get money owed to him from some of his associates, wants Patricia to run off with him to Rome, all the while seemingly cavalier about the fact that his name and photograph are in the local media as a cop killer. When Patricia eventually learns about Michel being wanted by the police, she has to decide where her allegiances lie.
The car thief Michel Poiccard kills a policeman on road RN7 between Marseille and Paris. He continues to Paris, where someone owes him money, and where he has fallen in love with Patricia Franchini, a young American woman, who is going to study at Sorbonne. Michel finds her at Champs-Élysée, where she is selling the New York Herald Tribune. She is not sure whether she loves him or not, and anyway she has an appointment with an American journalist, who has offered her some occasional job as a reporter. When she returns to her hotel room in the evening, she finds Michel lying in her bed. Next morning police detective Vital contacts her, as she has been seen together with Michel Poiccard. The detective shows her a newspaper with a photo of Michel, identifying him as the killer. She is forced to admit that she has met Michel, but says that she has no idea of where he is. Now she knows for sure that she loves Michel. She helps him to continue his flight.
A small-time thief steals a car and impulsively murders a motorcycle policeman. Wanted by the authorities, he reunites with a hip American journalism student and attempts to persuade her to run away with him to Italy.
- Michel Poiccard (Jean-Paul Belmondo) is a petty thief who makes money by stealing cars and driving them to Paris to resell. When during a job Michel is pulled over by a motorcycle policeman he shoots him dead and must find a way to escape the closing dragnet. In Paris Michel pilfers more money from an old girlfriend, and mugs a stranger in a rest room, and looks up American girl friend Patricia Franchini (Jean Seberg) an aspiring journalist who hawks the New York Herald Tribune on the Champs Elysees. Michel needs to collect money for his car but also emotionally is drawn to Patricia having slept with her previously and seeking some more stable bond but Patricia is apprehensive about their eventual success together. After Michel has collected his money and makes plans for him and Patricia to go away together, Patricia learns from the Police about Michels crime background and must make a heartfelt decision that may change their lives forever.