The last few nights there have been minor car burning and stone throwing in Copenhagen (mostly), Aarhus and Kalundborg, but at least the problems in Copenhagen had started even before the arrests and presumably have more to do with some teenagers basically being bored.
Obviously I don't hope this escalates. I actually live dead center in the part of Aarhus where the arrests were made (Gellerup) and of the 12 apartments in my stairway judging from the names on the doors, I'm the only native Dane.