François-Xavier Hussherr, 54, cofounder of an artificial intelligence startup, will stand trial before the Paris assize court from January 11 to 15, 2027, accused of murdering his wife, Cécile Poisson, a judicial source told AFP on Monday, August 3, 2026. He faces life imprisonment.
Poisson was an associate professor of comparative literature at Université Gustave-Eiffel in Marne-la-Vallée, Seine-et-Marne. Both she and Hussherr were former students of the École normale supérieure and had passed the agrégation, she in classics and he in economics.
A killing disguised as a delivery
The attack happened on March 20, 2023, around 9 a.m. in the 12th arrondissement of Paris. The couple had married in 1997, had three children, and had been separated for nearly two years.
According to details from the investigation obtained by AFP, Hussherr wore a motorcycle helmet, a surgical mask and a Deliveroo delivery bag, and waited for his wife in the lobby of her building before stabbing her several times in the throat and chest. He fled the scene and was later arrested inside a church by police who had been alerted by witnesses who chased him.
Blood was found on Hussherr's coat, shoes and bag, and he had wounds on his hands. Police found a bloodied knife on him, along with a motorcycle helmet, gloves and a box cutter in his bag.
Investigators find evidence of premeditation
During the investigation, Hussherr admitted to killing his wife but denied any premeditation. He said he had wanted to talk with her, including a plan to hold her for an hour, in order to propose a "win-win" financial arrangement, according to the source. Testimony gathered in the case indicated Hussherr feared the financial impact of the divorce despite his comfortable situation.
Hussherr, who heads the AI startup ProfesseurBob.ai, which aims to offer students individualized teaching, said at the time of the killing he was affected by overuse of medication, including anti-anxiety drugs, and claimed to have heard a voice telling him someone wanted to kill him. Psychiatric experts concluded he had no condition that could have affected his judgment and ruled out a psychotic episode, suggesting his statements may have reflected an "opportunistic approach." The investigating judge determined the crime was premeditated.
Victim had said she feared her husband
Investigators found that Hussherr had hired a private detective to spy on his wife and had scouted the location beforehand. An assistant at his startup said Hussherr had asked him to come to his home on the day of the killing to send pre-written emails and use his phone, which Hussherr admitted doing in order to build himself an alibi.
People close to Poisson said she had described being afraid of her husband, whom she called dangerous, citing psychological and physical abuse. In a letter dated 2021, she asked that an investigation be opened if she were to die.
Defense calls him "a broken man"
Hussherr's lawyers, Roxane Best and Alexandre Simonin, told AFP they regretted that a narrative was forming before any debate had taken place in court. They said the trial would run five days before a court and jury, where every piece of evidence would be argued on both sides, and they are contesting the charge of assassinat, a premeditated killing, rather than meurtre.
His defense said Hussherr dreads the hearing, describing him as a broken man who has lived with what happened for three years without ever trying to minimize its horror. They said he would appear before the court without evasion and answer every question put to him, including the hardest ones, adding that his thoughts are first with his children.
Maud Touitou, the lawyer representing civil parties including Poisson's parents, declined to comment, saying she would reserve her statements for the assize court.
