In Frankfurt itself - Palace Fkk , which is about 10 mins on the tram heading north out of the city.. I found this a bit too dark and claustrophobic for me to spend more that 1 session in. don't recall it being smokey , and certainly you couldn't use your phone in there.. if you had important email/calls to take then you could use the changing rooms i guess.. that's the only place you can use your phone. Has a decent enough selection of girls but I wouldn't go back based on the moody atmosphere alone.
I quite like going to Mainhattan - a convenient 20 min tram ride out east of the city. I always found a good varied selection here, all seemed to be in 20's-30's- mostly friendly Roms, and i kinda like them. The venue is big enough with a nice outdoor area for chilling, & BBQ - not sure for winter though. inside its light and airy. The girls can still smoke but i don't recall it being an issue like Artemis where you couldn't breathe. The Bar/seating area is comfy and clean, and has decent 'Wellness' facilities where the girls afford you a bit of peace and quiet. couple of saunas, steam room and the last time i was there they had a fantastic Thai lady doing the massages. Again there is no phone usage in the public spaces.. Ive seen people use the changing rooms for calls etc.. but an office space it is not.
I haven't yet been to Sharks in Darmstadt - a short cab or train ride from Frankfurt, but I consistently hear is that its probably the best in area for quality.. someone else here can probably speak to that.
The only FKK I've been to that I was surprised to see you could use your phone/tablet (so I'm guessing a Laptop too) was in Sixens on the Dutch /German border, near Aachen.
