French media is reporting that a woman crying "Allahu akbar" — "God is great" in Arabic — has hurt two people with a box-cutter at a supermarket in southern France.

Radio station Europe 1 quoted Bernard Marchal, the prosecutor of Toulon, as saying that a male customer in the E. Leclerc store in La Seyne-sur-Mer received chest injuries from the attack at around 10:30am this morning.

He has been taken to hospital - but his injuries are not believed to be life-threatening.

A female cashier was hurt too, but less seriously.

"It is apparently an isolated person with proven psychiatric disorders," said Mr Marchal. "However, that does not exclude radicalisation," he added.

The 24-year-old attacker is now in custody after being overpowered by others in the supermarket. She is believed to have been unknown to police, who are searching her home to see whether the attack was linked to Isis.

"We do not know yet if they were a terrorist, but they are in any case terrifying, because this man who hadn't made any demands was attacked at a supermarket checkout," said Mr Marchal.

Last month, a knifeman shouting "Allahu akbar" killed one person and wounded four others during a Saturday night attack in a bustling Paris neighbourhood.