Prostitution is legal in Germany. It's also taxable. While it's fairly easy to collect a "sex tax" from brothels, "sauna clubs," and other sex purveying establishments, it's trickier to make sure freelance streetwalkers pay up. The city of Bonn has a solution: An automated street meter where prostitutes pay a nightly fee to ply their trade. The converted parking meters, which went into effect Monday, are expected to raise about $285,000 a year. How do they work? Here, a brief guide:

How do the meters work?
Each night before work, prostitutes are required to buy a ticket for about $9 from one of the meters, which are being set up in areas used by sex workers and their customers. That buys the prostitute a day of legal work time, regardless of the number of clients. Prostitution is only legal in Bonn between 8:15 p.m. and 6 a.m.

What's the punishment for failing to pay?
First time sex-tax dodgers will get a warning. Subsequent violations merit a fine (about $125) or even a ban from working in the sex trade. After the first night of use, a single meter yielded roughly $375. Bonn has about 200 working prostitutes, with an average of 20 walking the streets on any given night.

Is the tax controversial?
Freelance sex workers aren't happy. Juanita Rosina Henning of prostitute support group Dona Carmen says the meters amount to double taxation, since prostitutes already pay income tax. Bonn is casting the meters as a fairness measure that puts streetwalkers on an even tax footing with sex workers in fixed establishments. Henning disagrees: "This has nothing to do with fiscal equality." 

Is prostitution controversial?
It has been legal in German since 2002, and the biggest complaint has reportedly been about prostitutes having sex with clients on residential streets — and even in people's yards. Bonn dealt with that by establishing prostitution zones on the outskirts of the city, and even constructing "consummation areas" — six garage-like wooden boxes for drive-up johns to park in during their assignations, complete with an alarm for the prostitutes if things get too rough.

Will this plan have any effect on prostitution?
Some commentators think so. That's what's so "remarkable" about the system, says Ryan Avent in The Economist. In "normal markets," we'd expect taxation to decrease a service. But there's also the real chance the sex meters could increase prostitution "by regularizing the system." Either way, kudos to the Germans: "Would sex workers in other countries pay on the honor system this readily?"

SourcesAFPBBC NewsBusiness InsiderCBC NewsCNNDaily Telegraph, Der Spiegel,  Economist, The Local