The 33-year-old admitted to starting a fire that destroyed 500 square metres (5,000 square feet) of vegetation in the Herault region on Tuesday evening, Beziers prosecutor Raphael Balland said.
He has also been accused of starting another blaze earlier in the day, but has denied any responsibility, claiming he was drunk.
The man, who used to volunteer as a firefighter in another part of France, was remanded in custody on Thursday and could face up to 10 years in jail when he goes on trial next month, the prosecutor said.
He is the second firefighter to be charged with arson in the Herault region.
Late last month, French authorities detained a forester in his 30s, whose job included preventing fires, after he admitted to starting blazes on three separate occasions for the adrenaline rush. He faces up to 15 years in prison
and a 150,000-euro ($153,000) fine.
France has in recent weeks battled soaring temperatures and several devastating forest fires.
Prosecutors last month said two fires in the normally blustery and shower-prone Brittany had also been sparked by arson.
Scientists say climate change is making heatwaves around the world more frequent and more intense, which increases the risk of fires.