Belgium's privacy watchdog has begun legal action against Facebook, accusing the social network site of tracking its users across the web and even monitoring the activities of those without an account.
The independent Privacy Commission, which is working with German, Dutch, French and Spanish counterparts, accused Facebook last month of trampling on European privacy laws after trying to find out more about the U.S. social media giant's practices.
"We did not get satisfactory answers so this was the next step," said a spokeswoman for the Commission for the Protection of Privacy (CPP).
The Commission has asked the court, which will convene on Thursday, for an immediate order banning Facebook from monitoring non-users in particular, which it may do via plug-ins or cookies.
The action is the latest of a series of legal and regulatory challenges across the European Union to U.S. technology companies, from the newer taxi-hailing service Uber to established Amazon and Google.
Facebook said it was surprised and disappointed that the CPP had agreed to a meeting on Friday and then taken the "theatrical" action of taking Facebook to court the day before.
It said it was confident there was no merit in the case, but was happy to work to resolve the concerns through a dialogue with its regulator, the Irish Data Protection Commissioner.
Facebook has previously described cookies as an industry standard and that Internet users had the right to opt out.
Facebook says it is subject only to law in Ireland, the site of its European headquarters, although some EU members have accused Dublin of being soft on multinational firms it has attracted, whether on data protection or corporate tax.