A student at a secondary school in southern France was arrested Thursday, a police source said, after a shooting that officials said left the headmaster and two students injured.
Schools in the town of Grasse, near Cannes, were locked down after the incident, and local educational authorities asked parents to stay away.
"Students are safe. Thank you to parents for not coming yet so that security forces can operate," the head of local educational services, Emmanual Ethis, wrote on Twitter.
Ethis also wrote that the parents of two children injured in the incident had been informed.
The police source told dpa that the arrested student was a 17-year-old who was carrying a rifle, a handgun and two hand grenades, and was not previously known to the police.
Interior Ministry spokesman Pierre-Henry Brandet told broadcaster BFMTV that a "heavily armed" student opened fire at his headmaster.
Police were continuing a search in the area in case a second person had been involved in the shooting, he added, stressing that there was "still absolutely no confirmation" of that.
It was not immediately clear how many people in total had been injured.
The French Interior Ministry also warned people, also via Twitter, to stay away from the area.
A police and emergency services operation was taking place there, the ministry said.