Pierre Brochant, a Parisian
publisher, attends a weekly "idiots' dinner", where guests, who are modish, prominent Parisian businessmen, must bring along an oblivious "idiot." The ideal "idiot" is usually one who is obsessed by a ridiculous hobby or theme, whom the other guests can ridicule subtly all evening without the idiot catching on. At the end of the dinner, the evening's "champion idiot" is selected among the businessmen. With the help of an "idiot scout", Brochant manages to find a "gem", François Pignon, a sprightly employee of the
Finance Ministry (which Brochant, a
tax cheat, loathes). Pignon has a passion for building
matchstick replicas of famous landmarks. Shortly after inviting Pignon to his home, Brochant is suddenly stricken with debilitating
back pain while playing golf at his exclusive
country club. His wife, Christine, leaves him shortly before Pignon arrives at his apartment, considering his still wanting to go to the "idiots' dinner," an unabashedly cruel aspect of his personality. After Pignon arrives, Brochant initially wants him to leave, but instead becomes reliant on him, because of his immobilizing back injury and his need to resolve his relationship issues. plays Pierre Brochant, a Parisian publisher, who invites Pignon to his weekly "idiots' dinner" with calamitous results. Brochant spends the evening trying to locate his wife, Christine, who has left him. (right) plays François Pignon, the “idiot” invited to discuss his matchstick replicas of famous landmarks, who unintentionally wrecks Brochant’s life.
Daniel Prévost (left) plays Lucien Cheval, a tax inspector who provides the address of Christine’s suspected lover. Cheval detects expensive
objets d’art on which Brochant has not paid taxes. plays Juste Leblanc, Brochant’s former best friend, from whom Brochant stole away Christine years before. plays Marlène Sasseur, Brochant’s former mistress, who Pignon mistakenly contacts, leading to the disclosure of Brochant’s infidelity to Christine. Brochant solicits Pignon's assistance in making a series of telephone calls to locate his wife, but Pignon blunders each time, including revealing to Christine the existence of Brochant's former mistress, Marlene Sasseur. Thinking Marlene is Brochant's sister, since her name sounds like "
sa sœur", Pignon mistakenly calls her and reveals Brochant's condition. Marlene announces that she is coming to help care for Brochant. When Brochant learns of Pignon's blunder, he asks Pignon to chase Marlene away, not wanting to complicate matters with "a nymphomaniac". Before Marlene's arrival, Christine briefly returns home; mistaking Christine for Marlene, Pignon gives "Marlene" advice on how to be less demanding to win back Brochant. Now informed of her husband's infidelity, Christine leaves. When the real Marlene arrives, an exasperated Brochant realizes what happened and asks Marlene to leave. In the meantime, fearing Christine might have gone back to her previous lover, Brochant coaches Pignon in a ruse to call his former best friend, Juste Leblanc, from whom he stole Christine, to determine whether Christine is with him. Phoning to impersonate a film producer who wants to buy the rights to a book Christine co-wrote with Leblanc, Pignon blunders by giving Brochant's phone number to Leblanc. Recognizing the number, Leblanc calls Brochant to say that it hurt when Christine left him too. Unexpectedly sympathetic, Leblanc arrives to try to help Brochant locate Christine. Making matters even worse, to get the address of a
lothario with whom Christine might have taken refuge, Pignon invites tax inspector Lucien Cheval to Brochant's house, compelling Brochant to quickly to hide most of his valuables in an attempt to disguise his tax evasion. Through an ironic coincidence, Cheval's own wife is with the Lotario, upsetting Cheval and increasing the likelihood of a tax audit for Brochant. Through the evening's events, Brochant is forced to reassess his mistakes. Brochant almost succeeds in reconciling with Christine when Pignon (unprompted) calls her to describe all the efforts Brochant has made that day to straighten out his life, including breaking up with his mistress, reconciling with his best friend, and wanting to make amends to her. A skeptical Christine asks Pignon whether Brochant is by his side, coaching him. Though Brochant is next to him―amazed at how gracefully Pignon has managed to describe his repentance to Christine―Pignon lies and says that he left Brochant and is calling from a phone booth. Christine hangs up in a pensive mood. Chastened, Brochant apologizes to Pignon for his arrogance and says that they will attend the next idiots' dinner together with him as Pignon's idiot. When a softened-up Christine calls Brochant at home to discuss reconciliation―true to form―Pignon absent-mindedly picks up the phone that is next to him. Christine immediately hangs up, wrongly convinced that Brochant has manipulated Pignon's eloquent account of Brochant's reformation. The film ends with Brochant again calling Pignon an idiot and blaming Pignon for ruining his life. ==Cast==