This looked staged to me. I think I saw about three punches landed, very soft, and the police presence reminded me of the days of basic training and crowd control training.
Watch the idiot in the yellow shirt. He doesn't land a single punch, doesn't even attempt to, then walks around flexing like he just won the world title. lolol.
If it is legit, then, they fight like pussies. But it looked very strategically staged. I dunno. Maybe there were a couple of agents provocateurs in there who might have got the show started. It doesn't look natural at all, though.
The two in the beginning of the video who invited the first punches were in blac bloc garb and they quickly, rather immediately, exited the scene right before the chaos started there after. Then the show started. Ha. Crazy...
Be diligent, folks. Really pay attention and watch what goes on in these videos as they come out. This one I just posted, from the op's link, looks completely staged.