French police officers of the anti-crime squad, Brigade Anti-Criminalite de nuit arrest a suspect in a street of Paris. AFP

The French anti-terrorism prosecutor opened an investigation concerning murder with a suspected terrorist motive, the prosecutor's office said.

The gruesome killing of the teacher occurred in the town of Conflans-Sainte-Honorine while the suspect was killed by police in adjoining Eragny. The towns are located in the Val d’Oise region northwest of Paris.

President Emmanuel Macron was headed to the area.

A police official said the suspect, armed with a knife and an airsoft gun — which fires plastic pellets - was shot dead about 600 meters (yards) from where the male teacher was killed after he failed to respond to orders to put down his arms, and acted in a threatening manner.

The teacher had received threats after opening a discussion "for a debate” about the caricatures about 10 days ago, the police official told reporters. The parent of a student had filed a complaint against the teacher, another police official said, adding that the suspected killer did not have a child at the school. The suspect's identity was not made public.

The two officials could not be named because they were not authorized to discuss ongoing investigations.

Agencies