Among its list of complaints, Europe v. Facebook alleges that Facebook has still not provided 40,000 people a full accounting of the data it holds on them after those people requested the data. European law mandates that data controllers must show people the data they hold within 40 days of the request.

When activists with Europe v. Facebook began requesting copies of their personal data last year, the social networking site would in some cases provide an exhaustive CD worth of data.

As the group gained notoriety, more and more people requested their data, and Facebook warned it wouldn't be able to quickly provide it due to the volume of requests.

Subsequently, Facebook created a tool that lets users download information from their profile, which it contends complies with the law. But Europe v. Facebook said the download tool only grabs 22 of 84 categories of data that the site records, and that Facebook should disclose more.

Facebook officials could not immediately be reached for comment.