Adapted from Maupassant's book of the same name, La Vie is deeply pessimistic and naturalistic right up to the last minute, when a note of hope strikes, although I'm nevertheless half convinced that this is the author being ironic.
Jeanne Le Perthuis des Vauds (Judith Chemla) leaves her convent school and rejoins her kindly parents Simon-Jacques (Jean-Pierre Darroussin) and La baronne Adélaïde (Yolande Moreau), only soon to marry what appears to be the first suitor to come along: Julien de Lamare (Swann Arlaud). After an idyllic honeymoon, flashes of which will be revisited onscreen numerous times as Jeanne remembers the past in her present hell – and this story is mainly of her hell – she is confronted by the reality of her situation.
And that reality is that Julien is mean (bullying Jeanne for using too much wood for heating and too many candles), bullying (treating the domestic Rosalie (played by Nina Meurisse) very harshly), and hypocritical and philandering (he won't entertain the idea of the expense of allowing Rosalie's 'bâtard' to live with them, and yet he's actually the father). This she, pregnant with their first and only child, finds out from the curé, who in an austere scene in which Jeanne's parents are also there, begs her to forgive Julien. Under great pressure, she does forgive him.
Things seem to return to the early happiness, with Jeanne playing almost chidishly with their friend Gilberte de Fourville (Clotilde Hesme), the wife of Georges (Alain Beigel), and all four have a great time playing croquet together. Until Jeanne discovers that Julien is up to his sexual tricks again, having an affair with Gilberte. She starts to waste away, admits the truth to the priest, and says that she believes that life is made up of lies. The priest, seeing the effect this is having on her, urges her to stop the lies and tell Georges the truth. She can't as it would hurt him too much, so the priest says he's going to do it for her: the result being that Julien, Gilberte and Georges all finish by shooting themselves to death.
Back at home, Jeanne learns after the death of her mother that she had been having an affair many years before, with a man who said she was not fit to live with Simon-Jacques. Ah, happy families! But Jeanne has to cope with her own son Paul (played by three characters as he grows), who at the age of eleven doesn't want to go to school and is very much of a problem child. At twenty he leaves with his girlfriend (later his wife) for London, although Jeanne disaproves of her because she thinks she's just eating up a great deal of money.
Paul won't be seen again, although his presence will be felt enormously. Thinking he'd make his fortune in London, he in fact amasses huge debts, and of course it's the every faithful Jeanne who'll have to foot the bills, causing her to age, to worry constantly, and at the end have to sell the property which has been in the family for many generations.
Rosalie – who is in fact Jeanne's foster sister – has returned to live with Jeanne as a friend, and she is firm with Jeanne in telling her that she can't send Paul any more money. Paul's wife dies, he's of course penniless, and sends the baby on to Jeanne. We're left with the two woman making silly faces at the young girl. Maupassant concluded La Vie with the sentence 'La vie, voyez-vous, ça n'est jamais si bon ni si mauvais qu'on croit' ('You see, life is never as good or bad as you think'.) No? First the monster Julien, then the monster Paul, and now a new generation: how will this one turn out?