Albi, France: A female teacher has been stabbed to death in front of her pupils at a primary school in the southern French town of Albi by a student's mother, who was immediately detained.

"This morning, a mother showed up with a knife and stabbed a 34-year-old teacher in front of her students, for reasons that will be determined by the investigation," Albi prosecutor Claude Derens said on Friday.

"When I arrived at the scene they were trying to revive her. She was in cardiac arrest in her classroom," he said.

President Francois Hollande immediately sent Education Minister Benoit Hamon to the school to take charge of the government response.