Facebook vowed to fight restrictions imposed by Germany’s competition regulator covering the company’s practice of linking data collected by WhatsApp and Instagram with its core platform without express user consent.

Bundeskartellamt issued the instruction today (7 February) following a nearly three-year investigation. It said Facebook services including WhatsApp and Instagram can continue to collect user data, but “assigning the data to Facebook user accounts will only be possible subject to the users’ voluntary consent”.

If consent is not given “Facebook will have to substantially restrict its collection and combining of data. Facebook is to develop proposals for solutions to this effect”.

The regulator said the ruling also applies to data collected from third party sources.

Bundeskartellamt president Andreas Mundt explained its decision was made because “the combination of data sources substantially contributed to the fact that Facebook was able to build a unique database for each individual user and thus to gain market power”. The practices also “impedes competitors that are not able to amass such a treasure trove of data.”

Facebook must lodge its appeal at the Dusseldorf Higher Regional Court within a month.

In a statement, the company blasted Bundeskartellamt, which it said “underestimates the fierce competition we face in Germany, misinterprets our compliance with GDPR and undermines the mechanisms European law provides for ensuring consistent data protection standards across the EU.”

“Popularity is not dominance. The Bundeskartellamt found in its own survey that over 40 per cent of social media users in Germany don’t even use Facebook. We face fierce competition in Germany, yet the Bundeskartellamt finds it irrelevant that our apps compete directly with YouTube, Snapchat, Twitter and others.”