Not sure yet but according to what's available this morning a demonstration took place on President's Hollande way to the november 11th ceremony at the Champs Elysees, it was organised (by Red Hoods the Breizh Nation movement) to protest the lack of truth related to a French foundry (located in the east part of France) that kept selling metals to German factories to make the shrapnel ammunitions used by German artillery (Congress library has a file over that company which I recall was part of the De Wendel empire but u should check if u can access it today) for at least two years after the conflict began and the strong priority with which the Breizh regiments were sacrificed.
According to others, far right militants were responsible for the incidents that took place this morning but not quite plausible until proved otherwise.
A small city south of France may have seen a terrorist attack during the november 11th ceremony, officials were attacked during the ceremony, two had to be hospitalised suffering several knife wounds although not life threatening according to witnesses. One man arrested but his iD has not been released and no mention of far right involvement accusation, very usual under these circumstances which points to a terrorist event by default.
If u get the name of that foundry, let me know despite my efforts can't recall the exact name and location.