“When Facebook took over WhatsApp in 2014, it pledged that the WhatsApp service would remain independent. Consumers trusted that their information would remain with WhatsApp alone and that no information would be transferred to Facebook. Their trust was broken,” the vzbv wrote in a statement on Monday.
The consumer watchdog has given WhatsApp until Wednesday to issue a declaration that it will not implement the changes to user terms. If it fails to do so, the vzbv will begin legal proceedings against the firm, the Frankfurter Allgemeine Zeitung (FAZ) reports.
The new user terms allow Facebook to lift phone numbers from a WhatsApp user's phonebook in order to more accurately target friend suggestions and business advertising.
However, fact-checking website Snopes.com points out that users can opt out of the data transfer by un-ticking a box that allows WhatsApp to share information with Facebook "to improve my Facebook ads and products experiences."
“We are extremely concerned about this insidious trend: consumers are losing step by step the ownership of their data. Their private sphere is in danger,” the consumer watchdog's statement reads.
WhatsApp claims that data-sharing is to the advantage of the user, meaning that they will see adverts from companies they have already been in contact with rather than from ones they have never heard of.
This is not the first time Facebook has been warned over how it treats WhatsApp user data by the vzbv, which is an umbrella organization for 41 consumer associations nationwide.
As early as the beginning of 2015, just a year after Facebook bought the messaging service in February 2014, the consumer protection organization expressed its first concerns about data transfers.
The vzbv also won a court case against WhatsApp in April, after it took legal action against the company for not publishing its terms and conditions in German.
The organization has previously been critical of Facebook's claim on its homepage that “Facebook is free and always will be”.
“Users don't pay for Facebook. But Facebook earns billions every year by exploiting the collective data of its users and selling them in the form of personalized advertising space to companies,” vzbv chair Klaus Müller warned in January 2015.