On Monday, French officials found two explosive devices outside a tax office on the island territory of Corsica.

French counterterrorism prosecutors have taken lead of the investigation. But as Le Monde reports, this isn't the first attack of its kind. Another tax office in a different area of France was targeted in this manner back in February. So what's going on here?

Well, there is suspicion that the attacks are related to the "gilet jaunes" or "yellow vest" protest movement. That's a deep tragedy. Because it shows the increasing extremism that defines the populist anti-austerity, anti-tax movement. As more-moderate yellow vest activists have moved away from the group, which is shown by reduced protest sizes, those remaining are centered around a hard-liner cadre.

But we in the U.S. should be clear about two things. First, that there is absolute legitimacy in taking to the streets with strong voice to demand a redress of grievances. Second, that there is no legitimacy in the violence we've seen in Corsica, home of France's greatest son Napoleon Bonaparte.

Whatever we think of President Emmanuel Macron's policies, those who use violence to promote their views and destroy their monuments are not patriots. Which, incidentally, should remind everyone that Vladimir Putin's hand lurks close by in supporting the yellow vests.