A group of people, who identify as "leftists" and "anarchists", have become upset that Muslim immigrants living in Germany are supporting their home country, Germany, in the World Cup. So upset, in fact, that they've taken the liberty to tear down and even burn German flags which the immigrants have put on display in support of their national team.
To these vandals, the flag represents the nationalism of the Third Reich. That may be so, but doesn't it hurt their credibility a little that they're fighting against their Nazi past by commiting attacks on minorities in this Kristallnacht-like manner?
I would normally expect this kind of behavior from the skinheads or other such groups. There are clearly the same motives involved: neither these left-wing fascists nor the right-wing fascists can accept Muslim immigrants as their fellow countrymen.