Germany hasn't eliminated nazi protests or hate symbols being displayed at them (or other nazi cultural events - nazi concerts seem really big right now), it's pretty easy to find references to them online. It doesn't seem like the government responds with mass arrests or shutting down the protests/concerts/display of nazi symbols. There's one famous holocaust denier mentioned in one of the articles that they seem to go after occasionally, but he's obviously not locked up for long.
It seems that the police primarily respond the same way they do in the U.S. - to prevent the protest from interfering with regular life and the rights of others - in the case of the bottom article, police intervened not to arrest people for protesting, but to protect a migrant shelter.
(These are all from just the last year or so, and there's many more).
German soldiers performed Nazi salute | JerusalemOnline
Neo-Nazis rally in Dresden ahead of war anniversary | Germany | DW | 11.02.2017
Neo-Nazis rock small town in Germany | News | DW | 15.07.2017
Report: Number of neo-Nazi rock concerts on the rise in Germany | News | DW | 20.08.2016
Neo-Nazi-rock-concert-draws-massive-crowds-in-Germany-499924
German neo-Nazi protesters clash with police at new migrant shelter | World news | The Guardian
This stuff doesn't seem to get a ton of press in the U.S. But let's not pretend that enlightened Europe, as much as they love to talk down to us, has figured out the Nazi issue.