A French nursery school teacher who claimed on Monday he was stabbed in his classroom by an Islamic State supporter has admitted to prosecutors that he invented the story.

The 45-year-old teacher at a school in Aubervilliers, northeast of Paris, was hospitalized with light stab wounds in his side and throat.

He had earlier claimed that a man in overalls and a balaclava had arrived while he was preparing his class on Monday, grabbed a box cutter and scissors that were in the room, and attacked him.

The teacher further claimed that the man shouted: �This is Daesh. This is a warning.� Daesh is an Arabic term for IS.

Prosecutors said they were still questioning the teacher, whose injuries were not considered life-threatening, over why he lied.

With France on edge a month on from attacks in Paris, and with the IS calling for attacks on French schools, the investigation had been immediately taken over by anti-terrorism prosecutors.

The case even prompted a visit by Education Minister Najat Vallaud-Belkacem, who vowed to boost security at France�s schools.

The Islamic State�s French-language magazine Dar-al-Islam called in its November edition for its followers to kill teachers in the French education system, describing them as �enemies of Allah.�

�This education, in the case of France in particular, is a means of propaganda used to impose the corrupt way of thought established by the Judeo-masonry,� it said.

�Muslims must know the French education system is built against religion and Islam as the only religion of truth cannot cohabit with this fanatic secularism.�

Last month�s attacks by IS in Paris, that left 130 dead, saw France impose a three-month state of emergency and led to a Europe-wide manhunt for suspects.

�We will continue to reinforce security measures at schools in a context where schools feel threatened,� said Vallaud-Belkacem on Monday.

Rachel Schneider of the main primary school teachers� union SNUipp said the IS threats had alarmed faculty members.

�We have received many calls from colleagues, who are very worried. They don�t necessarily think there will be an organized attack, but they fear this message of murderous madness will inspire unstable people to action,� she said.

In March 2012 jihadist Mohamed Merah killed three children and a teacher outside a Jewish school in southwestern France in attacks which also saw him kill three soldiers.

(AP)