Frankfurt is the financial hub of Germany. It is not the largest city in Germany, but it is visited by people from all over. So it follows that there is plenty of prostitution in Frankfurt too. I have no way to know what percentage of the visitors travel to Frankfurt to patronize the sex industry there, but I would guess that it is not high.
People go to Frankfurt for all kinds of reasons but sex is not usually one of them. In fact, Frankfurt is rarely mentioned as a sex industry hot spot. Germany long ago legalized prostitution.
On the hand, a lot of what goes on can be hidden in plain sight. There are all sorts of commercial sex venues scattered around the city that the casual observer would probably not even notice. What started in nudist colonies has indirectly led to the creation of sex clubs that proliferate all over the country and even in nearby countries like Austria and the Czech Republic. Women who want to sell sexual services pay a fee to enter these clubs.
Men also pay a fee to enter in hopes of meeting some of these ladies. Inside the guys have free run of the facilities that usually include lounges, pools, outdoor areas, theaters and free food and drink. The women walk around naked or in lingerie. The women and men can request sex from each other either in public or private rooms. The rates are usually around 50 or 60 Euro for thirty minutes of oral and vaginal sex with other services coming at a premium.
Frankfurt is home to many of these FKK sex saunas including several that are generally well regarded. Depending on how you define the term there are several brothels in Frankfurt. Typically these take the form of private houses. They can be staffed by a single lady or by several ladies. Some places even have themes or are organized are particular principles. In the example of Japan Miss the women on staff all hail from Asia.
