A 17 year old student, carrying a rifle, two handguns and two grenades has reportedly been arrested over the incident.
The headmaster was among the eight people injured in the attack, confirmed the French Interior Ministry.
France is still in a state of emergency after a series of terror attacks including the November 2015 massacre in Paris and a truck attack in Nice, just 40 kilometres (25 miles) from Grasse, in July past year.
"The individual does not seem to be known by police", one police source said. Local police told people on Twitter to stay home and the area around the school has been cordoned off. "I thought about my friends and the teachers too", Camel said.
One student reported hearing four gunshots, while another student, speaking to Nice Matin (in French), described hearing three loud bangs before turning and seeing a shooter.
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Expect breezy conditions with the wind out of the west at 15-20 miles per hour , gusting to 35 miles per hour . According to the watch, light rain and snow will begin to fall this evening, and quickly change to all snow.
Two people have been injured in the attack and police has shut down the school for now.
All schools in Grasse were closed after the shooting incident.
France remains in a state of emergency following deadly terrorist attacks over the past two years.
Two people were wounded in the shooting but all students are safe, a government minister said.
Both local residents would not provide their names.
And never forget the 130 who were gunned down in cold blood in Paris on November 13, 2015.