In the wake of his killing, some teachers acknowledged they censored themselves to avoid confrontation with pupils and parents over religion and free speech.

School children across France paid tribute to the late history teacher Samuel Paty on Friday to mark the passing of a year since he was beheaded by an Islamist radical in an attack that struck at the heart of the country's secular values.

Paty's attacker, a teenager of Chechen origin, had wanted to avenge the teacher's use of cartoons of the Prophet Mohammad in a class on freedom of expression for 13-year-olds. Muslims see any depiction of the Prophet as blasphemous.

At a new school in Valenton, south of Paris, that has been named after Samuel Paty, children sang a song about freedom of speech in ceremony for the slain teacher on Friday.

"It is moving because Samuel Paty was killed in such a horrific way. And so singing for him makes you very emotional," said 6th grade student Yona Sehi.

Paty was decapitated by Abdullakh Anzorov with a large knife on a street in a middle-class Paris suburb in broad daylight. Police shot dead the 18-year-old soon afterwards.