One person was killed, and at least four others were injured in a shooting in the Yvelines district west of Paris, and a suspect has been arrested, French Prime Minister Sebastien Lecornu said on Friday.
Ali Rabeh, the mayor of the Yvelines town of Trappes, told BFMTV that a man had fired shots from his car and "appeared to be firing at random and seemed intent on carrying out a massacre".
He said one of those injured was a 12-year-old girl, adding that the shooter lived in a nearby town. There was no information so far about his motives, he said.
Lecornu wrote on X that security forces had been fully mobilised. "The national anti-terrorism prosecutor’s office has announced that it is monitoring the situation," he added.
Representatives for the prosecutor's office did not immediately respond to a request for comment, and the prefecture declined to comment. The anti-terrorism prosecutor's office confirmed it was monitoring the case.
What is happening with left-wing French protests?
Shortly afterwards, French Interior Minister Laurent Nunez said on Friday that 70,000 security forces would be mobilised throughout the country to keep order on Saturday, adding there have been calls for looting and violence from the ultra-left.
"Look at social media: There have been calls from the far-left to target public buildings. We are not talking about a nice protest," Nunez told reporters.
"We are ready tomorrow to be extremely firm and not tolerate anything."
France is still reeling from the worst violence in years last weekend, when looting and riots took place on the fringes of nationwide protests, though overnight curfews in parts of Paris and other cities have since passed without major incident.
French President Emmanuel Macron blamed "seditious" ultra-left groups for the unrest - allegations the prominent far-left France Unbowed party denied - and said on Thursday that "illegitimate" protests would be banned in coming days. Demonstrations organized by groups such as trade unions would be allowed to proceed but could be diverted along alternative routes, he said.
Businesses, cultural events and museums planned to close at the weekend despite curbs on demonstrations as Macron seeks to restore order a week after nationwide protests turned violent.
France's main student union, UNEF, has called for rallies on Saturday, while the Yellow Vest movement, an anti-establishment force that emerged in 2018, filed plans this week for a march through central Paris.
Macron was due to meet student representatives later on Friday to discuss their plans but UNEF said their rallies, which grew from high school protests last month against teacher shortages and shabby facilities, would go ahead.