Bonn — On Thursday, Germany’s anti-trust watchdog  announced a crackdown on Facebook’s data-collection practices after ruling that the world’s largest social network abuses its market dominance to gather information about users without their knowledge or consent.

Facebook said it will appeal the landmark ruling by the Federal Cartel Office, the culmination of a three-year probe, saying the watchdog underestimates the competition it faces and undermines Europe-wide privacy rules (GDPR) that took effect last year.

“In future, Facebook will no longer be allowed to force its users to agree to the practically unrestricted collection and assigning of non-Facebook data to their Facebook accounts,” Cartel office chief Andreas Mundt said.

The probe’s findings come amid fierce scrutiny of Facebook over a series of privacy lapses, including the leak of data on tens of millions of Facebook users, as well as the extensive use of targeted ads by foreign powers seeking to influence elections in the US.

The cartel office objected in particular to how Facebook acquires data on people from third-party apps — including its own WhatsApp and Instagram services — and its online tracking of people who aren’t even members.

This includes tracking visitors to websites with an embedded Facebook “like” or share button — and pages where it observes people even though there is no obvious sign the social network is present.

The ruling does not yet have legal force and Facebook has a month to appeal, which the social network said it will do.

“We disagree with their conclusions and intend to appeal so that people in Germany continue to benefit fully from all our services,” Facebook said in a blog post.

“The Bundeskartellamt underestimates the fierce competition we face in Germany, misinterprets our compliance with the GDPR, and threatens the mechanism European law provides for ensuring consistent data protection standards across the EU.”