On 12 February 2026, Quentin Deranque, a 23-year-old French far-right activist, was beaten by several far-left individuals in what has variously been described as a "brawl" between members of the far-right and the far-left, or as a "lynching", in Lyon, France. Deranque was there "to provide security" for the femonationalist group Collectif Némésis. Many of the arrested individuals were linked to the outlawed far-left militant anti-fascist collective Jeune Garde Antifasciste (English: Anti-Fascist Young Guard). Deranque died from brain injuries two days later in hospital.
Deranque's death, initially reported as an attack on an isolated victim, rather than a brawl between two armed groups, provoked national political reactions in the lead-up to the March 2026 French municipal elections and a minute of silence held in the National Assembly. Politically, Deranque's death led to the isolation of left-wing party La France Insoumise (LFI), as the party was close to the Jeune Garde. On 17 February 2026, LFI leader Jean-Luc Mélenchon reiterated his party's "great affection" for the Jeune Garde. In late February 2026, Mélenchon accused the far-right feminist collective Némésis of having deliberately organised a "trap" (traquenard) by using its members as bait to provoke clashes with antifascist militants around Rima Hassan's conference in Lyon.
Part of the French political class accused the far-left, or the ultra-left, of being responsible, while the public prosecutor office and the police sought to identify the perpetrators. Justice minister Gérald Darmanin and interior minister Laurent Nuñez both commented on the early progress of the investigation, claiming that the far-left was behind the attack. Citing videos of the event, several journalistic investigations gradually called into question the initial version of events by Némésis, particularly regarding who was responsible for the clashes between the two groups. Further investigations revealed that Némésis had repeatedly coordinated with far-right groups in Lyon to provoke clashes with left-wing activists.