The suspected attacker entered the factory and set off several small explosive devices, the source said.
A decapitated body was found nearby the factory, another source said.
The total number of casualties was not immediately reported.
The attack came nearly six months after the attacks in and around Paris that killed 17 people in January that started with a shooting at satirical magazine Charlie Hebdo.
French Interior Minister Bernard Cazeneuve said he would go “immediately” to the scene, his office said.
Source: Al Jazeera