Screen grab from BFM TV shows police standing at the scene outside the factory where the man was beheaded
French interior minister Bernard Cazeneuve says the man arrested following an explosion and the decapitation of a man at a gas factory has been known to security services since 2006.
A decapitated head was found posted on the gate at the entrance to a gas factory after it came under attack in south-eastern France, security officials said.
The torso was found near the site of an explosion at the scene near Grenoble but the victim was not decapitated by the blast, officials said.
Two flags, one white and one black and both with Arabic inscriptions, were found at the scene.
Several people were wounded in the incident. French officials said it began mid-morning in the Isere region when two men crashed a car into the entrance of the factory and into gas canisters, touching off the explosion.
One attacker, known to authorities, has been arrested.
Police are searching for anyone else involved in the attack, and Cazeneuve has arrived at the scene.
France terror attacks: Interior minister confirms authorities have been aware of suspect for nine years
