Sorry, I only have german sources:

http://www.zeit.de/gesellschaft/zeitgeschehen/2014-01/gefahr... (recent developments)

http://www.zeit.de/gesellschaft/zeitgeschehen/2013-12/Rote-F... (about the original demonstration)

The underlying situation is pretty complicated and dates back to developments in the 80s (Hafenstrasse Hamburg etc.), I doubt there's good english references.