A primary school teacher in the southern French town of Albi has been stabbed to death in front of her class by a pupil's mother, police say, reports the BBC.
Fabienne Terral-Calmes, 34, was attacked at the Edouard Herriot school on Friday morning.
The suspect, 47, was arrested at home shortly afterwards, prosecutors say.
Education Minister Benoit Hamon said she appeared to have a "serious psychiatric disorder", according to initial investigations.
Sending the minister to the scene, President Francois Hollande pledged that all the services of the state would be "mobilised to take care of these children and the staff who witnessed this awful tragedy".
The attack came on the last school day before the summer break, when Ms Terral-Calmes was teaching her class, believed to be aged five to six. She herself was the mother of two young children.
The attacker was bringing her own daughter, aged five or six, to school as usual on Friday when she produced a long knife, French broadcaster France Info reports.
She is said to have shouted "I am not a thief" before attacking.
Ms Terral-Calmes was stabbed just once, either in the chest or stomach, according to different reports.
Albi prosecutor Claude Derens was one of the first at the scene.
"When I arrived at the scene they were trying to revive her," he said. "She was in cardiac arrest in her classroom."
Read more of this report from the BBC.