Clothing Optional Lodgings in European Cities

Hi all! I'm looking to experience a bit of Europe mostly as a tourist - staying in a city with culture and sights. I'd LOVE to stay in a clothing optional hotel, a gay or mainstream guest house where you can practice social nudity. But of course most places like that are at beach resorts or in the countryside. If you have any tips for urban nudist lodgings (prefer a more communal situation like a B&B vs. an apartment share), or urban nudism in general, I'd love advice!