fredbassett and I were in Prague this weekend. No hot men in leather were spotted, but we did manage to pin a location down. On a hunch and a photo in a brochure we went to Strahov Monastery near Prague Castle. It has two very ornate and beautiful libraries that looked vaguely familiar. Now we've got back home we were right - they were used as locations in A Rebellious Woman.
Library 1
Library 2
Unfortunately, unless you're on an organised tour, you can't actually go in the libraries, just stand at the door. I also have no idea where Ninon's library is/ :(