One person has been killed and two more have been seriously injured following an attack at a school in France.

A knife attack took place at the Gambetta school in the northern town of Arras on Friday, with a French language teacher killed.

According to both Le Parisien and BFMTV, the attacker is said to have shouted "Allahu akbar" during the attack, with the latter identifying the assailant as a 20-year-old former student of the school, believed to be of Chechen descent.

It's believed a staff member at the school is in a critical condition after sustaining multiple stab wounds, with a third person also seriously injured.

Those claims have so far not been confirmed by French officials.

Interior Minister Gérald Darmanin confirmed that the attacker was detained after the incident, with BFMTV reporting that his brother has also been detained.

Police have said the situation is now under control.