Everybody has been all a twitter this week about Berlin's "fixie ban." Even Freakanomics picked up on this story with a sensational headline.
German bike blogs like Rad Spannerei have reported that police in several major cities have been cracking down on brakeless fixies all over Germany, including in Berlin, as police have started to notice brakeless fixies in larger numbers, and the Polizei are tasked with maintaining Germany's reputation as a law and order society.
The "ban" on brakeless bikes in Germany is not new, although the crackdown is relatively recent -- I think it probably began about a year ago? Bikes in Germany must be equipped with brakes; although coaster brakes are common in Europe, the German police apparently don't agree with the claim that you stop the bike by backpedaling is the same as a coaster brake.