Since shortly after his election in 2007 – or roughly since his marriage to the singer Carla Bruni – Nicolas Sarkozy, the French president, has been on a crusade against the pirating of songs and films, particularly over the internet. Last week, after a bruising legislative battle, he won passage of a law called “Hadopi”, after the anagram of the enforcement agency it establishes. Whether it constitutes a sensible restitution of intellectual property to its rightful owners or a ghastly and vindictive invasion of computer-users’ privacy is a question that has divided France’s political parties.

Hadopi relies on online surveillance by copyright owners – usually film and music companies. It is quite easy, apparently, for these “content providers” to tell when their products are being illegally downloaded over unencrypted peer-to-peer systems such as BitTorrent. When record companies and film producers notice their wares being pirated, they can report the IP address of the offending computer to Hadopi. The illegal user is then required to load spyware on to his computer that will alert Hadopi to further infractions. One more brings a warning. Two bring a ban from the internet of up to a year.