Facebook has said it is suing the EU antitrust regulator for attempting to gain information beyond what is necessary for its case against the firm.
The tech giant said this included seeking highly personal details from its employees, such as medical history and information about family members.
The European Commission has been probing Facebook since last year, with one investigation centred on its treasure hoard of data and the other on its online marketplace, which is used by 800m users to buy and sell items.
Facebook has provided 315,000 documents — equivalent to 1.7m pages — to the body as part of the process.
“The exceptionally broad nature of the Commission’s requests means we would be required to turn over predominantly irrelevant documents that have nothing to do with the Commission’s investigations, including highly sensitive personal information such as employees’ medical information, personal financial documents, and private information about family members of employees,” Facebook general counsel Tim Lamb said in a statement.
“We think such requests should be reviewed by the EU courts.”
The Commission said it would defend its case in court. News of the lawsuit was first reported by the Financial Times.
EU regulators will be combing through documents looking for about 2,500 search phrases which include “big question,” “shut down” and “not good for us,” a person familiar with the matter told Reuters.
The person said such search terms could be found in employees’ health information, performance evaluation and even job applications to the company which are not relevant to the EU investigations.
Facebook is also separately seeking interim measures at the Luxembourg-based General Court, Europe’s second-highest, to halt such data requests until judges make a decision, according to a court filing.
The social media giant is set to face US politicians in an antitrust hearing on Wednesday, at which chief executive Mark Zuckerberg will face questioning.
He will appear via video link alongside the chief executives of Apple, Amazon and Google.