funny enough, neo-nazism is on the rise in germany - a neo nazi party has taken regional level parliament seats
actually, it's declining... the NPD (if that's the party you mean) barely made the entry barrier of 5% for Saxony last year, after 9.2% in 2004 (1999: 1.4%). It's the first time ever that they were able to stay in a state's parliament for a 2nd term.
Saxony is a state in east germany, the former GDR, and even though west german states are subsidizing the east with billions since 1990, they are still seeing much higher unemployment rates (east: 10.7%, west: 6.1%), crime rates, etc. in comparison, which usually is a driving factor for people to get stupid ideas.
That said, there has been an ongoing legal debate for many years whether the NPD should be illegal. They somehow always managed to argue that their political views are within the law. The law being that right-wing extremism is highly illegal. In germany, that part of the political spectrum is gagged/outlawed to a much higher level than in many other countries, just because of its history. Personally, I've seen nazi gangs a couple of times in the UK, but never in germany.
Also, the NPD party actually has less members than the KKK in the US... not saying that they are comparable. Just to put their size into perspective.