About 10 years ago, I was in Frankfurt for a few days.
Got the chance to visit The Palace and Oase.
I can't remember what the entrance fees were back then,
but I know it was 50euro for each session with a girl.
Basically about 30mins.
Soft drinks and food were included.
As far as the girls, there was plenty of variety, I'm sure there is someone there for all tastes.
Most girls were from eastern Europe (Romania, Bulgaria, etc) from what I remember.
I did meet one from Cali, Colombia.
Attitudes varied a lot. Some you could tell was strictly about their business, most were pleasant enough.
I think there is some sort of "don't harass the customers nonstop" type of thing set in place by the clubs.
I have a fond memory of one girl that hung out with me and just chatted until I left.....
Was it worth it? IMO, absolutely yes.
If nothing else, just for novelty of the experience.
Its kinda like going to a strip club for the first time in your life, except much better.
I don't know how much inflation and geopolitics in the the EU has affected the scene.
But I would put going to an FKK on the must do before you die list for any man.
Ignatzmice or other EU forums probably has current info.