I don't know if that bother us too much as to discuss about legalizing it at a municipal level but I can tell you that in the beach I used to go (
Zarauz) I saw nude sunbathers. They used to lay in one end of the beach, not separated by any wall, wire or warning signs at all, close to a restaurant owned by a famous cook who used to have a TV program where he taught how to cook. Sometimes he cooked at the porch outside the restaurant with that particular part of the beach in the background. Nobody spotted a nudist in his TV program, though.
I have never heard of anybody being arrested for being naked in that beach, so I guess that I was allowed, or if it was a law against, it wasn't enforced.
I haven't been around the mediterranean beaches in a long time, but I have heard that topless sunbathing is pretty common over there.