Germany's Federal Court of Law, the Bundesgerichtshof (BGH), has ruled that users of file-sharing sites have no right to remain anonymous, regardless of how much – or little – music they share.

The ruling comes in the case of Naidoo Records vs Deutsche Telekom. Naidoo Records had requested that the German ISP hand over the names and addresses of users of an IP address behind the illegal file-sharing of a piece of music, a new album by German song writer Xavier Naidoo.

The local courts in Cologne - first the Landgericht Köln then the superior court Oberlandesgericht Köln - refused Naidoo Records' request, saying that the breach of copyright would need to be on a commercial scale before the ISP could share the identity of the IP address owner.

The BGH has now overturned the local courts' decisions, ruling that Naidoo Records' request should be granted. The court decided that a breach of the law is sufficient for the details to be handed over, and the question of whether the breach was on a commercial scale or not is not relevant.

The rights holder is entitled to compensation and an injunction if their copyright is infringed, the court ruled, regardless of the magnitude of the infringement.

The BGH's decision has generated strong reactions: Lars Klingbeil, spokesman for the opposition Social Democratic Party (SPD), has called for a revision of German copyright law, saying the BGH's position is in conflict with that of the German parliament. Klingbeil claims the parliament wants to only punish copyright infringements that occur on a commercial scale.

The German Department of Justice (Bundesjustizministerium) is currently working on a revision of the copyright law, but this has been delayed for years.

On the other side, the German music industry association Bundesverband Musikindustrie has welcomed the ruling.

Thanks to the BGH's decision, the association said, it will be easier to protect older music records: in the past, most German judges only allowed top 100 or new albums to be protected by the 'commercial scale' legislation.