Facebook has been ordered to stop collecting and storing data on WhatsApp users in Germany, marking the first regulatory challenge to a controversial data-sharing scheme that the social media company announced in August. In a statement published Tuesday, Germany’s privacy watchdog said that sharing WhatsApp user data with Facebook, the messaging app’s parent company, constitutes “an infringement of national data protection law.” The regulatory body also ordered Facebook to delete all data that has already been transferred from WhatsApp.

Facebook’s data-sharing scheme has been closely monitored by privacy groups across Europe. When Facebook acquired WhatsApp in 2014, the app’s co-founder, Jan Koum, assured users their privacy would not be compromised. Under the policy announced in August, however, WhatsApp will share some user data – including phone numbers – with Facebook, and plans to allow businesses to contact users directly through its app. WhatsApp has said that the arrangement will allow Facebook to deliver more targeted advertising and friend suggestions, and that analytics data will help combat spam and fraud. But privacy advocates have criticized the companies for not being transparent about the change.

Other privacy regulators have raised concerns over the data-sharing scheme. CNIL, France’s data protection authority and the chair of a group of privacy regulators across Europe, said in August that privacy watchdogs will be monitoring the change to WhatsApp policy ‘with great vigilance.” The Information Commission’s Office (ICO), Britain’s data privacy regulator, also said it would monitor how data is shared across the two platforms, though it does not have the authority to block the scheme altogether. In an email statement, a Facebook spokesperson said that the company will appeal the order from Germany’s privacy watchdog.

As of now, the United States has not weighed in on this issue, so it’ll be interesting to see what happens. Privacy is a big issue in today’s age and needs to be talked about. Apple, Google, and many other companies have been against companies storing and using user data for different purposes Hopefully in the future more companies will join them.