http://www.newser.com/story/127376/germany-installs-street-meters-for-prostitutes.html

Prostitution is not only legal in Bonn, Germany, the city has implemented a new "sex tax" for prostitutes who want to ply their trade. City officials also have come up with a novel way to get their money: They've installed automated meters in red-light districts, akin to parking meters, reports Der Spiegel. Prostitutes who want to work must plug in about $9 and get their nightly permit. Those caught without one face fines of about $150.

"It's not fair that some women who work in establishments like sex centers or sauna clubs are taxed only because we can find them more easily there," explains a city official. Plus, many of the streetwalkers come from other countries and struggle with the appropriate paperwork. The permit-dispensing meters makes it a snap.