A high school principal and two others were wounded in a shooting in France but there is no reason to suspect terrorism, a police official said.
People were warned to stay indoors after the attack on Thursday at Alexis de Tocqueville school in the town of Grasse.
One teenager has been arrested, police confirmed, and another is reported to be on the run.
Frightened people were tweeting from inside the school.
The arrested suspect is a 17-year-old student and was carrying a gun, a pistol, a revolver and two grenades, French media reported.
France Info quoted town hall officials who said two pupils entered the school, intent on shooting another pupil and the principal was wounded when he intervened.
The French Interior Ministry issued a warning for the area, telling people to follow instructions from authorities through media and social media.
Police urged people to avoid the area.
The shooting happened just after a letter bomb exploded at the Paris offices of the International Monetary Fund.
Police confirmed one person was injured in the blast caused by a suspected firecracker earlier this morning.