Cologne, a city of around 1 million people (which makes it one of the 10 largest cities in Germany) introduced a special "sex tax" in 1993 applying to all sex clubs, gay saunas, swinger clubs, etc.
Despite initial protest from the club owners the tax provided a windfall of €700,000 (~US$ 925,000) for the fiscal year of 1994!
There's money to be made from sex - even city councils are realising it!
[news snippet found on gmx.net]