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The main German data protection regulator for Facebook bans the social network from processing personal data of WhatsApp users because it considers the new terms of use of the messaging app to be illegal, he said on Tuesday.

The move follows emergency proceedings opened by the regulator in the city-state of Hamburg last month after WhatsApp forced users to agree to new terms or stop using the service.

“This ordinance aims to guarantee the rights and freedoms of the millions of users who give their consent to the terms of use across Germany,” said Johannes Caspar, data protection officer in Hamburg.

“My goal is to prevent the inconvenience and damage associated with such a black box-type procedure.”

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Caspar, who heads national oversight of Facebook under the German federal system while his country office is in Hamburg, announced his decision ahead of the May 15 deadline to consent to the new WhatsApp terms.

WhatsApp, which is owned by Facebook, said the Hamburg data protection authority’s action was based on a fundamental misunderstanding of the purpose and effect of its update and therefore had no legitimate basis.

“As the claims of the Hamburg DPA are false, the order will not impact the continued rollout of the update. We remain fully committed to providing secure and private communications for all,” said a door – speech of WhatsApp.

The regulatory action has opened a new front in Germany over Facebook’s privacy policies, with its national antitrust regulator waging a legal battle over data practices it says is an abuse of market dominance.

As of 2018, online privacy has been subject to a European Union rulebook called the General Data Protection Regulation (GDPR). Under GDPR, Ireland is leading the oversight of Facebook because the company’s European headquarters is there.

Caspar said he was using his power to impose a three-month freeze on Facebook’s collection of WhatsApp user data under extraordinary powers under the GDPR.

He said he would also seek an EU-wide decision from the European Data Protection Board, a forum that brings together regulators from the bloc’s 27 member states.