A French teacher has died of injuries from third degree burns after setting herself on fire in front of frightened students.

The 44-year-old teacher, who had worked at Jean Moulin school for 10 years, was depressed over her relations with her students in her math classes.

Jean Moulin is in the town of Beziers, south of France.

The BBC reported that the yet-to-be-named teacher went to work Thursday morning with a jerry can, held a class at 9am, and then at break time, she walked into the playground while dousing petrol from the can, then set herself ablaze in front of shocked students.

"It seemed totally strange and unreal. I saw a body on fire going forward with her hands on her head. Several of us tried to put it out. She kept saying, 'No, leave me, I don't need your help. God told me to do this,'" a student named Karim told Agence France Presse.

The teacher was taken by helicopter to a nearby Montpellier hospital, where she died overnight.

"(The teacher) had third-degree burns over 95 per cent of her body," a hospital source told AFP. "With these burns there was no way she could have survived."

AFP reported a teacher at the school as saying teaching was one of the few professions in which the mental health of teachers is not assessed or monitored.

In a joint statement, unions representing secondary school teachers said the incident put in focus teachers' hardships over working conditions.

The Jean Moulin incident is the third time in a year someone in a French school has set themselves on fire. In January, a school-boy set himself ablaze in Marseille and in November, an 18-year-old student in Bordeaux also self-immolated.