The psychiatric examination found that his "judgement had been impaired and that he was not in a fit state to be in custody", prosecutors said. They added that further psychiatric assessment would be sought. The teacher said he had been attacked while alone in a classroom in Aubervilliers, a suburb of Paris. But prosecutors said he had wounded himself with a box cutter. The 45-year-old teacher - who has not been named - was treated in hospital for superficial wounds to his side and neck.
The mayor of Aubervilliers, Pascal Beaudet, said the teacher had 20 years' experience and was "appreciated" by parents at the school. The education ministry said the man had been suspended. The incident sparked a manhunt in the northern suburb, as police tried to track down the alleged attacker. All classes at the Jean-Perrin preschool were cancelled.
Last month, the Islamic State's French-language magazine Dar-al-Islam urged followers to kill teachers in France, describing them as "enemies of Allah" for teaching secularism. Rachel Schneider, of the French primary school teachers' union SNUipp, said many teachers had been alarmed by the threat.
"We have received many calls from colleagues, who are very worried," she said.
Comment: Similar stories from across the pond:
Cop fabricates crime, shoots himself, and says it was suspect who doesn't exist
Cop commits suicide, stages death to look like he was killed in the line of duty