Facebook is facing yet another privacy headache in Europe.
German authorities opened an antitrust probe into the company on Wednesday.
Germany's Federal Cartel Office said Facebook (FB) might be using its dominant market position to force users to agree with terms and conditions that allow the company to use personal data for advertising purposes.
The office said it was concerned that Facebook's terms and conditions are not clear enough for users.
"It is difficult for users to understand and assess the scope of the agreement accepted by them," it said in the statement.
The watchdog said Facebook is collecting "a large amount of personal user data from various sources" to make money from targeted advertising.
"There is an initial suspicion that Facebook's conditions of use are in violation of data protection provisions," the statement read.
Facebook said it is confident that it complies with the law. "We look forward to working with the Federal Cartel Office to answer their questions," a Facebook spokesperson said.
Related: U.S. promises to dial back spying on European data
Facebook is facing multiple privacy challenges across Europe. The German watchdog said it was working with the European Commission and competition authorities in other European Union countries on the case.
At the same time, data protection authorities in Ireland, Belgium and Germany requested a review of the way Facebook handles their citizens' data.
In a separate class action against Facebook, roughly 25,000 Europeans accused Facebook of not respecting their privacy rights and sharing their data with third parties.
