Agence France Presse report:

#BREAKING One dead, several hurt in attack on French factory: legal source

— AFP news agency (@AFP) June 26, 2015

#BREAKING Attacker on French factory carrying Islamist flag: legal source

— AFP news agency (@AFP) June 26, 2015

#BREAKING Decapitated body found near attacked French factory: legal source

— AFP news agency (@AFP) June 26, 2015

Developing…

UPDATE: More from French newspaper Le Dauphine:

“The head of the victim was found hanging on the fence of the Company enclosure along the RD311. Technicians criminal identifications gendarmerie Grenoble just arrived on site…

According to a source close to the investigation, a car burst into the company shortly before 10:00. A man was beheaded inside the court, he is not an employee of the company. His head was allegedly found several dozen meters from his body.”

UPDATE II:

“an individual of thirty years known to the security services was arrested”

UPDATE III:

“the head of man was found decapitated covered with Arabic inscriptions”