Isabel (Hudson) visits her sister, Roxeanne (Watts), a poet who is living in Paris with her husband, Charles-Henri, and her young daughter, Gennie. Roxy is pregnant, but her husband has just walked out on her. She holds the lie that he is "in the country" selling a painting. Isabel discovers the truth and agrees to go see Charles-Henri with Roxy to give him his contacts which he left behind.
Arriving, Charles-Henri makes an excuse to leave when Paris-based American author Olivia Pace (Close), a friend of Roxy's, arrives. Olivia offers Isabel a job which she takes. Later, the sisters go to the country to visit Charles-Henri's family for Sunday brunch. It is there that Isabel meets Charles-Henri's mother (Leslie Caron), along with Charles-Henri's uncle, Edgar.
Later, while helping Olivia, Isabel meets Yves, another one of Olivia's workers. The two have sex, and afterwards while watching television Isabel sees Edgar giving a speech and admits she is attracted to him. The two have lunch and begin an affair, but Isabel still strings Yves along. Edgar sends a Hermes Paris Kelly bag to Isabel, which is an expensive item Roxy knows Isabel can't afford, and Isabel tells Roxy of their affair.
Meanwhile, Roxy meets Charles-Henri's own mistress, Magda Tellman. Magda's husband, an American, begins to stalk Isabel's apartment complex. One afternoon, Roxy meets Charles-Henri at a park where Gennie rides a carousel. The two talk and Roxy says she doesn't want a divorce, but Charles-Henri does. Roxy admits she's been thinking about names and likes Henri-Luc. Charles-Henri is still not entertained and leaves. Later that evening, Isabel finds a bloody, unconscious Roxy on the sofa and calls an ambulance. Roxy lives and apologizes for her attempt at suicide and is aided by her lawyer.
Isabel calls the family to Paris to help with Roxy. This only further complicates things, especially when Edgar's wife, Amelie, discovers the affair through Edgar's sister and Roxy's mother-in-law. Along with this, Olivia's own long-gone affair with Edgar is exploited, and Charles-Henri is found dead, murdered by Magda Tellman's husband in a crime of passion. Mr. Tellman follows the Walkers up the Eiffel Tower where he corners them and pulls a gun, demanding to have an opportunity to explain to an absentee Roxy why he killed her husband. After some persuasion, Tellman slides the gun over to Isabel who puts it in her Kelly bag before throwing it off the Eiffel Tower.
Subsequently, Edgar ends his affair with Isabel with a Chanel scarf and a blunt, brief lunch. Charles-Henri's mother still stays involved with her new grandson, presumably named Henri-Luc or Luc's, life. Roxy marries her lawyer, Isabel begins a real relationship with Yves and the family painting by La Tour of Saint Ursula sells for almost USD 4 million. This prompts the family to begin a foundation for Saint Ursula based in Paris.