Many of the girls come from Eastern European EU countries such as Romania & Bulgaria.
Most prostitutes who come from outside EU, are from Ukraine, Russia & South America.
Most German cities however established "Sperrbezirke" (off-limits zones) and charge the street prostitutes an amusement tax, that in the city of Bonn for instance is paid by the streethookers at parking meters, 6€ for a period of about 8 hours at nightime.
The same fee is collected from sex workers in apartments and brothels, sometimes by municipal tax collectors in person.
Some street whores have a nearby caravan, others use the customer's car, still others use hotel rooms.