Police say the mother of a pupil at a French pre-school stabbed a teacher to death in front of her class Friday, the last day of the school year.

French President Francois Hollande expressed outrage at "this abominable drama" and sent the education minister to the school in Albi in southern France, about 80 kilometres northeast of Toulouse.

A police official in Albi said the mother attacked the teacher Friday morning at the Edouard Herriot pre-school.

"Yes, it was the mother of a pupil who did it," said the official, who was not authorized to be publicly named speaking about ongoing investigations.

The official would not comment on possible reasons for the attack.

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French Education Minister Benoit Hamon addresses reporters at the prefecture of the Tarn region in Albi, southwestern France, on Friday. (Eric Cabanis/AFP/Getty Images)

The teacher was leading a class of five- and six-year-olds, according to the Albi mayor's office. Prime Minister Manuel Valls says the teacher was 34 years old.

"When I arrived on the scene, they were still trying to revive her. She was in cardiac arrest," local prosecutor Claude Derens told Agence France-Presse

May face 30 years in prison

The killer was reported to have fled the scene and avoided arrest for about 20 minutes before police found her near her home. She was also reported to have a previous police record.

The woman, whose age has been given as 47, is being held for trial and may face as much as 30 years in prison.

Such deadly attacks in a school are extremely rare in France, which still feels scars from a shooting at a Jewish school in Toulouse in southern France in 2012 that left three children and a rabbi dead.

RTL radio reported that the mother previously had problems with the police after allegedly abandoning her 15-year-old child earlier this year and failing to help police search for the child.

Fellow teacher Robert Couffignal told BFM television that the school had never seen such violence, and urged better protection for teachers and attention to the tensions they face with parents.