When I first got here, I started wondering about people in bikinis and speedos trying to catch a tan anywhere they could (public parks, river sides, etc) and I wondered about what would happen if someone would want to do it topless. My doubts dissipated yesterday.
If you are planning on having a swim on the Rhein now that it's so hot, beware of walking between Roche and Tinguely museum close to the river. I was walking along the Rhein yesterday when I came across a bunch of naked people (and when I say people I mean old dudes, but that's not really the point) In a country that it's so strict with certain things, I really was surprised to see this sort of "nude city beach".
It's doesn't really bother me, this is just an announcement if you don't wanna see someone else's privat parts "al fresco".