For young Parisian boy Antoine Doinel, life is one difficult situation after another. Surrounded by inconsiderate adults, including his neglectful parents, Antoine spends his days with his best friend, Rene, trying to plan for a better life. When one of their schemes goes awry, Antoine ends up in trouble with the law, leading to even more conflicts with unsympathetic authority figures.

Various experiences of childhood are seen in several sequences that take place in the small town of Thiers, France. Vignettes include a boy's awakening interest in girls, couples double-dating at the movies, brothers giving their friend a haircut, a boy dealing with an abusive home life, a baby and a cat sitting by an open window, a child telling a dirty joke, and a boy who develops a crush on his friend's mother.

Paul, a young idealist trying to figure out what he wants to do with his life, takes a job interviewing people for a marketing research firm. He moves in with aspiring pop singer Madeleine. Paul, however, is disillusioned by the growing commercialism in society, while Madeleine just wants to be successful. The story is told in a series of 15 unrelated vignettes.