Prostitution in Germany is fully legal, and accepted as a part of paying for your own pension. All forms of sexwork such as escort, brothels, massage parlors but also advertisements for prostitution is considered legal. The goverment charges tax as it is a regulated business. Girls who plan to work or consider working in germany also have to apply with the law about having documents and a subscription in the country first.
There are alot of forms of sexwork in Germany. Mainly clubs and brothels which are among the most populair. Escort agencies and erotic massage (outcall) as well but also incall services. Germany holds alot of various girls working from various (and usually eastern european) countries. If you plan to work in Germany you have to oblige to a legal residence & stay. From there on you can signup as a legal sexworker.
Below here is a list of populair, known & legal agencies & brothels that accept girls. However only under the condition that you furfill your documents at first. These agencies will not do this for you. Once your resident & legal your welcome to apply for work as sexworker in Germany. The law is very specific on this that agencies cannot involve in any form of human trafficking in Germany. The penalty's for this are very serious.