German data protection authorities have blocked Facebook from collecting subscriber data from its subsidiary WhatsApp, citing privacy concerns.

 

Facebook and WhatsApp promised in the wake of the Silicon Valley giant's 2014 acquisition of the messaging app that they would not share data, Hamburg's Commissioner for Data Protection and Freedom of Information Johannes Caspar recalled in a statement.

 

He added that Facebook would be required to delete any data already received from WhatsApp in Germany.

 

"It has to be (the users') decision whether they want to connect their account with Facebook," Caspar said. "Facebook has to ask for their permission in advance."

 

WhatsApp announced in August that it would begin sharing data with Facebook, in a bid to allow better-targeted advertising and fight spam on the platform.

 

Currently, users of the instant messenger must opt out of sending information to Facebook through WhatsApp's settings on their smartphone.

 

Caspar said that he had acted to protect the privacy of 35 million WhatsApp users in Germany -- a fraction of some one billion worldwide -- and that of people saved in their address books, whose details might also be forwarded under the data-sharing arrangement.

 

Facebook's activities in German-speaking regions are managed through its subsidiary in Hamburg, placing the firm under the jurisdiction of the regulator in the northern port city. 

 

 A Facebook spokesperson told The Guardian: “Facebook complies with EU data protection law. We will work with the Hamburg DPA in an effort to address their questions and resolve any concerns.”

 

WhatsApp's announcement that it would share information with Facebook came just four months after the service introduced end-to-end encryption by default, saying that the content of messages would become unreadable for anyone except the sender and receiver.