It was a funny moment in May when Mark Zuckerberg bumped into German Chancellor Angela Merkel at the G8 meeting in France. Merkel told the 27-year-old billionaire about how much she enjoyed The Social Network; Zuckerberg hadn't liked it much at all. A telling moment: over the years, Germany and Facebook have often been at odds with each other. Not surprisingly, most of their disagreements have to do with privacy.

The latest development has to with Facebook's facial recognition feature that helps users tag photos. After joining in the chorus of European nations that objected to the feature launch in June, German authorities are now the first to declare the feature illegal. Hamburg's data protection official Johannes Caspar claims that the software violates both German and European Union data protection laws and that Facebook users don't know how to delete the data that Facebook is gathering. "If the data were to get into the wrong hands, then someone with a picture taken on a mobile phone could use biometrics to compare the pictures and make an identification," Caspar told the Hamburger Abendblatt. "The right to anonymity is in danger."

Facebook has two weeks to respond before German authorities take legal action. The site could face up to half a million dollars in fines.

This is not the first time that Facebook has been on the wrong side of the law in Germany. Last July, Caspar launched a similar case against Facebook for saving data of people who hadn't even signed up for the social network. Like they're now doing more aggressively with their facial recognition feature, Facebook collected data about non-Facebook users through the Friend Finder feature and then stored it without permission. German authorities threatened legal action then, but it took Facebook nearly six months before they finally disabled the feature. In the meantime, German lawmakers proposed a moratorium on the use of Facebook during the hiring process, and also floated a ban on Facebook parties after 1,600 people showed up at a girl's sweet sixteen after a public Facebook event went viral.

Like we said, privacy has been the theme, here. Cyrus Farivar at Deutsche Welle explains:

Germany has among some of the strictest data protection and privacy laws in the European Union, largely created in the wake of informational abuses perpetrated by the Nazis and the Stasi, the East German secret police. One of the foundational concepts of German data protection law is that no data can be collected without the express consent of the user.

One could imagine that Facebook failing to respond to German officials' allegations could balloon into a damaging conversation about 21st-century surveillance. (Google, by comparison, avoided debate and quickly complied when accused of violating German privacy laws, halting their street view service.) Provoking any comparison to the Nazis or the Stasi would undoubtedly be a PR nightmare for Facebook.

Still, the company doesn't seem to be responding too quickly. "We have repeatedly asked Facebook to shut down the facial recognition function and to delete the previously stored data," said Caspar in a statement Tuesday. Facebook's PR team then told Spiegel Online that they "firmly rejected any accusations that we are not complying with our obligations to European Union data protection laws." Crafty of them to glaze over German law, there.