Facebook's legal battles in Europe enter another round today when Vienna district court hears a civil suit filed against the US company by Austrian privacy campaigner Max Schrems.

He accuses Facebook of operating a business based on data collection practices that are in violation of Austrian and EU privacy laws.

Mr Schrems has already taken on the US multinational in Dublin, where its international operation is based, and has a case involving Facebook ongoing at the European Court of Justice.

This morning’s initial hearing will be a technical matter on whether or not the Vienna court sees itself as entitled to hear the case, and whether the complaint is admissible as a class-action suit.

Dublin-based Facebook International disputes the involvement of the court, arguing that it is answerable to the Irish data protection commissioner and Irish courts. Counsel for Mr Schrems disagree. They have framed the case as a consumer complaint, entitling a complaint to be filed in the complainant’s home country and opening a door to the Vienna court.

Class-action lawsuits are unusual but not unheard of in Austrian courts and arose after Mr Schrems’s Europe-v-Facebook campaign set up a website allowing other Facebook users sign up.

To date, he says, more than 50,000 people have expressed an interest in joining, though this case has limited participation to 25,000 users. They are represented in court by eight parties today, from Austria, Germany and India.

The civil case demands compensation of €10 million from Facebook, what Schrems calls a symbolic sum of €500 per participating user.

For the Vienna-based campaigner, today’s case is part of a wider campaign to force a legal judgment on whether, in the age of Facebook, the European fundamental right to privacy exists in reality or just on paper.