European file-sharers were given a huge legal boost today, as the European Court of Justice declared that EU law does not allow Internet Service Providers to be forced to reveal the personal details of people accused of file sharing.

Telefonica, Spain’s largest telecom operator successfully argued that the law only required it to reveal the identities of those accused of a criminal offense and that sharing of music was a civil issue.

The European Court of Justice agreed with Telefonica in its dispute with the Spanish music rights holders association Promusicae. In order to start civil proceedings, Promusicae had asked for the names of Telefonica subscribers, who allegedly infringed copyrighted material by using KaZaA.

The court said that: “Community law does not require the member states, in order to ensure the effective protection of copyright, to lay down an obligation to disclose personal data in the context of civil proceedings.”

This ruling is a huge victory for EU filesharers, whose privacy is now backed by a ruling from the European Court. For ISPs this should be a huge relief as well, and they can finally put their time and effort in working for their customers, instead of against them.

The tide is changing for European filesharers. Last week we reported that the data protection commissioner in Switzerland criticized the infamous anti-piracy tracking outfit Logistep for helping to breach the privacy of filesharers. A few days before that decision, Greens EFA, a coalition of two political parties that currently have 42 seats in the European parliament, launched a pro-filesharing campaign named “I Wouldn’t Steal”.