Six teenagers go on trial behind closed door today, accused of involvement in the beheading of French history teacher Samuel Paty by a suspected Islamist in 2020 in an attack that struck at the heart of the country's secular values.

The teacher had shown his pupils cartoons of the Prophet Mohammad in a class on freedom of expression, angering a number of Muslim parents. Muslims believe that any depiction of the Prophet is blasphemous.

One of the minors is a 15-year-old girl who allegedly told her parents that Paty had shown caricatures of the prophet in her class. She will be charged with false accusation after it was established that she was not in the class when it happened.

Paty, 47, was killed outside his school in a Paris suburb by an 18-year-old assailant, born in Russia of Chechen origin, who was shot dead by police soon after the attack.

The five other minors to be prosecuted, aged between 14 and 15 at the time of the attack, will be charged with premeditated criminal conspiracy, or ambush.

They are suspected of having pointed out Paty to the murderer or helped monitor his exit from the school.

All six minors were referred to the children's court and could face 2.5 years in prison.

The hearings, due to last until Dec. 8, will be held behind closed doors.

Eight adults are also accused and will appear before a special criminal court.

France is home to Europe's largest Muslim minority and has suffered a wave of attacks by Islamist militants or their sympathisers in past years.

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