I would certainly defer to your superior knowledge of things Continental, Sylvain
With the Clockwork Orange and soccer hooligan comments I was speaking to the impression I have that many of the participants just want to mix it up more than that they are ideologically inspired. I will say, when I see them in action, British street thugs seem to have way more experience at their craft
I've never spoken with Antifa folks, either European or Americans, do I don't know about their ideology.
Some people in Europe are almost professional rioters.They travel all over Europe (a lot are from Russia) in large groups to go to different events (social protests, soccer games, whatever) just to fight with cops, protesters and supporter of soccer teams.
They rent a bus and cross several EU borders to go wherever there's a large gathering of people.
A lot of them are parts of "black block" groups and sometimes have been in more riots than the local anti-riot cops.