Try this link
http://21orover.com/discus/messages/43/44.html
Tons of good info there.
An extract from the site regarding the legality and some definitions.
Legal Status
Prostitution per se is legal here, but pimping, promoting prostitution, and trafficking are not. Prostitutes still must pay taxes and get health checks. Authorities often raid sex-related establishments to remove foreign sex workers without legal documentation. Many Eastern European nations will join the EU this year, so there should be fewer undocumented workers in all types of employment.
Legalized prostitution takes many forms here. They include:
Hobbyhüren.
This German term refers to women who normally work out of their own homes or apartments as independents. They are typically students looking to earn extra money or bored housewives/single women looking for more sexual fulfillment. They normally advertise over the Internet or in the Personals section of sex-related publications.
Escorts.
These women work either independently or for an agency. They typically visit upscale hotels to service well-heeled business travelers. They tend to be very attractive and charge fees at the higher end of the scale. They normally advertise over the Internet or via pamphlets available in certain hotel lobbies.
Red Light Districts.
Most major German cities have at least one. They're typically located near main train stations and are concentrated into areas spanning several blocks. They consist of strip clubs, sex shops, and walk-up apartments where women ply their trade. Service tends to be inexpensive, but it can also vary widely in quality from adequate to very poor. The Reeperbahn in Hamburg is notorious for poor service.
Streetwalkers also belong in this category. In certain areas of the country (for example, in the city of Würzburg), they operate out of small trailers parked alongside the road in out-of-the-way areas.
Traditional Brothels.
These are smaller establishments that usually employ three to five (or more) women. They often feature a certain nationality (for example, Asian). There is usually no entry fee and the price per session is set according to time and/or activity. There is often a small bar where one must pay for drinks. These establishments normally advertise over the Internet or in sex-related publications, taking care to downplay the prostitution aspect.
FKK Sauna Clubs.
These establishments are housed in coverted large homes or industrial properties. They're typically concentrated in the Rhein-Ruhr area (Frankfurt-Cologne-Düsseldorf), although a few exist in the former East Germany or in Bavaria (Munich area). They typically include amenities such as full-alcohol bars, showers and towels, swimming pools, wet and dry saunas, fitness equipment, and buffets, and they encourage guests to stay as long as they like in exchange for an entry fee.
They use the term "FKK" (which refers to nudism, a socially-acceptable hobby in Germany) to promote themselves and downplay the prostitution aspect. Depending on their floor space, they employ anywhere from a half-dozen to several dozen women, who appear fully nude to entice customers. Prices are reasonable and quality of service varies from adequate to very good. These establishments normally advertise over the Internet or in sex-related publications.
Swingers' Clubs.
These establishments are referred to as "Partytreffs" in German. Although they charge guests an entry fee, they're not brothels. Rather, they're a venue for consenting adults to indulge in sex without exchanging money. Still, club management occasionally hires attractive prostitutes to liven things up.