British author Lucy Foley's novel The Paris Apartment was published in 2022 and became an instant New York Times Bestseller. Foley’s popular mystery-thrillers, which also include The Guest List and The Hunting Party, use classic mystery-thriller tropes and are infused with social commentary about class strata and the human propensity for self-deception. The Paris Apartment explores how humanity’s loyalty and inherent survival instincts can be exploited for wealth and security. This guide refers to the 2022 William Morrow Kindle edition.

Content Warning: The source material includes misogynistic language and suicide, and its central plotline involves sex trafficking.

Plot Summary

The novel consists of many short chapters, each titled after the character whose point of view directs that chapter. The narrative perspective is therefore continually shifting, and many chapters end on cliffhangers that remain unresolved until several chapters later.

The novel opens with Ben Daniels, a journalist who has recently moved to Paris, on the cusp of writing a powerful story when a figure breaks into his apartment. When his half-sister Jess Hadley arrives for a visit, she discovers that he is nowhere to be found—even though his wallet, key, and Vespa are all in their proper place. Believing that Ben has been disappeared, Jess asks around about his whereabouts, but she is out of place in the apartment building: She is less wealthy than the residents, she is a foreigner, and she asks questions the residents want to avoid.

The residents are disturbed by Jess’s arrival. They each have their own experiences with Ben and their own closely guarded secrets. Sophie Meunier is an older woman whose husband, Jacques, pressures her to look glamorous at all times—but underneath her beauty, she is tormented, as an anonymous extortionist sends her notes threatening to reveal a secret about her. Mimi is a young woman who wants to be part of something exciting and social but is treated as a child and remains emotionally immature. Antoine has an alcohol addiction, and the reclusive concierge surveils all tenants with suspicion.

Jess’s search leads her into the staircases within the building’s walls; these staircases are a remnant of the passages servants used long ago. Jess descends a staircase to the cellar, where the door closes tightly behind her, trapping her. Though she is sure someone locked her in, she is rescued by a man named Nick, who insists that the door was only jammed. Nick and Ben are old university friends who traveled together in Amsterdam; he helped settle Ben into the apartment when Ben surprised him in Paris after a decade of no communication. Nick helps Jess report Ben’s disappearance to the police.

Jess develops a burgeoning alliance with Theo, a newspaper editor who worked with Ben on a freelance basis. When Jess discovers that Ben’s wallet holds a mysterious metal card with a firework symbol, she gives it to Theo to establish trust and find answers. They listen again to Ben’s last voicemail to Jess, and they can discern Ben confronting a figure who surprised him in his apartment—Jess’s only concrete evidence that something bad has happened to Ben. On her way back from meeting with Theo, Jess notices a woman following her. The woman is also looking for Ben and says she overheard Jess asking about him. When Jess says Ben may be in trouble, however, the woman runs away.

Jess ferrets around the building and comes across Sophie, who is hosting a party in her apartment. Though Nick, Mimi, and Antoine act like strangers at this party, Jess finds a photograph of them with a younger Sophie, revealing that they are, somehow, a family. Upon this discovery, Jess decides Nick is untrustworthy but decides against confronting him for the time being.

Mimi hosts a Halloween party in the building’s cellar, and Jess attends so she can ask around about Ben. At one point during the party, Jess leaves to snoop around Mimi’s apartment and finds cut-up painted portraits of a nude Ben. Jess realizes that Mimi has been watching Ben from her window and painting him. The next day, Theo tells Jess that he’s onto something: He uses the metal card from Ben’s wallet to get them into a secret club owned by Jacques. One of the club’s dancers is none other than the woman who followed Jess around, hoping to find Ben through Jess. Her name is Irina.

The chapters narrated by Mimi reveal that she was obsessed with Ben and believed him to reciprocate the feelings. Sophie’s chapters likewise expose that she had an affair with Ben, while Nick’s chapters recount a sexual experience he had with Ben when the two traveled together in Amsterdam. As the secrets continue to surface, the Meunier family dynamics slowly unravel: Antoine and Nick are Sophie’s stepsons; Mimi, whose biological mother died in childbirth, is the daughter whom Sophie adopted and passed off as her own biological child. Mimi’s grandmother is the concierge, who took the job to be closer to her secret granddaughter.

Irina later meets with Jess and Theo and reveals the truth of the operation: Women were brought in from abroad, on the belief that they would be dancers, but the club is really a front for sex trafficking where elite Parisian men use coded wine purchases to select which women to abuse for the night. The women are mostly undocumented, and their passports are held by their traffickers. Irina hands over photographs of some of the men, which she took with a camera Ben snuck in for her. After this meeting, Theo is arrested for drug possession, though he accuses the police of planting their evidence.

Meanwhile, Antoine reveals to Sophie that he’s her extortionist. He knows that Jacques met Sophie at the “club”—that Sophie herself was trafficked before Jacques married her. Antoine also knows about Sophie’s affair with Ben and threatens to tell Jacques about it.

Jess returns to the apartment building and finds the concierge injured at the foot of the stairs. When Nick and Antoine confront Jess, she runs all the way to the attic, the former maids’ quarters, where she finds Ben on the brink of death. Sophie and Nick enter the attic, and Sophie finally explains Ben’s initial disappearance: After Ben had moved into the building, Mimi found his exposé on Jacques’s sex-trafficking business, and when she told Nick, Nick told Jacques. Mimi then saw Jacques attacking Ben in his apartment and fled to Ben’s aid, killing Jacques. Sophie and the concierge helped hide the evidence and brought Ben to the attic, where Sophie has been tending to him. Sophie enveloped Jacques’s body in a bed sheet and led Antoine and Nick to believe it was Ben’s body; they buried him in the courtyard garden.

Ben recuperates in the hospital, and Theo helps him publish his story with a different angle, omitting the details about Mimi and Sophie and only exposing the club as a front for sex trafficking. Jess convinces Sophie first to give up the meticulous records of the traffickers, then to sell off her valuables and give the money to the trafficked women so they can get away before the cops raid the club. Shortly after Ben’s story is published, Antoine dies by suicide. The police believe that Jacques is in hiding somewhere, but an anonymous website publishes the records and photographs of the club’s predators.

Jess moves to Italy. At the train station, she sees the concierge and Sophie’s dog headed for the South of France, where Mimi has gone to recuperate.