On Saturday 17 October 2026, actu.fr writes that the large Grenoble demonstration against the high cost of living, “launched by groups of Yellow Vests and joined by the unions, university students and the high-school student movement” (translated), is taking place calmly; the Union syndicale des lycéens had called, like several organisations, to join that day the “large demonstration” (translated) of the “yellow vests” (translated) (AFP dispatch of 14 October, picked up by Sud Radio). According to the Isère prefecture, cited by actu.fr, “a group of about 300 hooded individuals, equipped and for the most part armed, quickly broke away” (translated) from the mobilisations in the early afternoon, then joined by others, “about 800 people” (translated) in the end; ICI Isère reports an estimate by the prefecture of 900 “vandals and looters” (translated).
According to ICI Isère, which gathers the testimony of a resident of the building, the costume shop and the window of a neighbouring clothes shop are first looted and smashed; around 5:45 p.m., “vandals” (translated) set fire to the shop and the fire completely engulfs the ground floor of the building. The firefighters, who arrived quickly, evacuate the occupants of the upper floors; the resident says he called 17 because “there was no police in the street” (translated), and ICI writes that a firefighter asked journalists to move away because of a risk of explosion. Le Dauphiné Libéré places the fire “at around 5:30 p.m.” (translated) on the ground floor of 16 avenue Alsace-Lorraine, in the party shop, and writes that it spread to several apartments and to the adjoining business, “also charred” (translated); the newspaper also headlines this statement: “They are young people, hooded and dressed in black, who went up to warn everyone” (translated) (subscribers-only article, read only in part).
The Isère prefecture tells BFMTV (update of 7:16 p.m.) that the building is on fire, that the residents are evacuated and that the fire started in a party supplies shop on the ground floor. France 3 writes the next day that a building on rue Alsace-Lorraine is “entirely ravaged by the flames” (translated) (photo caption) and “partly destroyed” (translated) (standfirst), and that “the flames entirely destroyed” (translated) the party shop. The same day, according to the prefecture, the town hall, the rectorat and the Saint-Louis church are targeted, bus shelters destroyed, vehicles set on fire and more than thirty shops and bank branches looted (France 3); ICI Isère counts 58 arrests and 30 police officers and gendarmes injured for the whole day, and specifies that investigators are analysing drone images to identify other suspects.
The sources read do not say who set the fire or by what means, and no specific arrest for this fire appears in them.