The Hamburg data protection regulator has said he had begun legal action against the social networking behemoth over its claim that the company collects and stores the data of people who are not even members of the site.
"We consider the saving of data from third parties, in this context, to be against data privacy laws," the Hamburg data protection office's Johannes Caspar said in a statement to news wire AP.
The people's details reportedly end up in Facebook's systems via users' email accounts.
"It is a system that is designed around making it possible for Facebook to expand, for its own benefit," Caspar told AP.
