A judge told Dutch cable operator and Internet broadband provider UPC, a unit of Liberty Global, to give the name and address of one its clients to an anti-piracy agency, according to a Reuters report.
The report said the result was a breakthrough for Dutch copyright holders interest group Brein, which had long tried to gain access to names and addresses of individuals whom it suspected of swapping large numbers of songs, films and other copyrighted material.
Lawyers said it was the first time a Dutch Internet service provider would have to hand over personal details of file swappers who stored copyrighted content on their own computers, the report said.
UPC said it had always refused to supply subscriber data because this would be a breach of Dutch privacy laws, according to the report.
But the Amsterdam judge said privacy rules did not apply if two conditions were met: copyright holders needed to prove, beyond reasonable doubt, that files had been swapped illegally, and also that the person swapping the files was the same person who was the registered customer.