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 amount to an abuse of market dominance. Since 2018, online privacy has been subject to a European Union rulebook, called the General Data Protection Regulation (GDPR). Under the GDPR, Ireland leads 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 foreseen in the GDPR. He said he would also seek an EU-wide ruling at the European Data Protection Board, a forum that groups regulators from the bloc’s 27 member states.