Don't know about Hanover, but I have been to Frankfurt and Hamburg. There is a thriving sex business in both of those cities, and I think it is perfectly legal. When I traveled to Germany a few years ago, I looked at lot at the World Sex Guide at worldsex.org for guidance. Hell, you could probably do a google search on Hanover escorts and find some stuff.
In Frankfurt, there was an entire apartment building downtown dedicated to sp's. The sp's would rent out rooms in this building, and you could walk up and down the stairs and each floor checking them out as they would be out on display in their doorways. This was kind of fun, as it appealed to the treasure hunter in me. These are relatively inexpensive, in and out in 15 minutes type places. I would assume Hanover might have something similar.
In both Frankfurt and Hamburg, there are also private clubs where you pay an admission fee, and go to a bar or lounge where there are tons of pros walking around. You chat one up, have a drink, and take her to a room. These girls are far better looking than the ones in the buildings. DFK, DATY, CBJ is what I recall. I don't remember the prices, unfortunately. I remember it wasn't super cheap, but it didn't break the bank either.
