However, I only went to Bernds, which is one of the more low key clubs and I'm Asian American and I had no problems with regards to the girls reception of me.  The biggest issue, and I don't think this is limited to the fact that I am Asian American, is that it helps a GREAT deal if you can speak some German(bonus points if you are fluent).  

I cannot speak any German and it greatly limited my interaction with the ladies.  For me, it was basically, "Hi", and then kiss and then getting right to the act (if you are interested). It was also a bit limiting if you have some preferences but they could not understand what you were saying.  

I imagine that if you went to one of the larger clubs in the larger cities, you will find more English speaking girls.  Bernds is much more expensive for entry fee than some of the other clubs, but it's very low key as the girls are not pushy at all and in fact, you have to initiate everything (plus the food that they provide is actually very good).

Good luck!

I'm Caucasian and have traveled in a group with Japanese and Indian-decent fellow mongers. I never saw any discrimination, although heard stories that if visiting alone, some clubs may discriminate against people of Arabic/Persian-looking extraction. I'm not sure about African or other ethnicities. I'd say overall, if you dress decently, are polite/well-spoken, and appear to have good grooming, etc., when you show up at an FKK's door, you won't likely have any problem. And if you should happen to encounter an issue, there are many other clubs from which to choose.

I happen to be caucasian, and have been to several clubs in the NRW and have never seen a problem. On my last visit to Golden Time, there were a several other male guests of asian, latin, middle eastern, and african heritage. No issues as long as everyone behaved approriately, was polite, respectful, and well groomed. At GT, the diversity also extended to the ladies, if that is of interest to you. Other clubs seem to have less diversity of clients, but I have met asian and middle eastern gentlemen at VV as well. Enjoy!