Some measure of dramatic violence is a routine part of "industrial action" (i.e. strikes) in France, at least when those strikes are considered to be targeting multinationals. In the past, management officials of 3M and Goodyear were kidnapped. Burning tires and the like are common as well (especially at Goodyear).

More generally, France is notorious for being suspicious of foreign influences (international Communism, globalization, Islamism -- heck, even Catholicism, though most of them still practice it at least nominally.)

Terrorism... I dunno, terrorists in small groups tend to blow up or gun down people unexpectedly, whereas these protestors in large groups don't generally try to kill or to hide.

<sarcasm> Terrorism is reserved for perpetrators with Islamic beliefs. </sarcasm>