French Internet users are taking a centuries-old tradition into the cyber age and erecting barricades against a new law aimed at clamping down on film and music piracy through illegal file sharing.

The law -- known as Hadopi -- is being touted as an example for other countries and the best way to protect artists' income but critics see the threat of having their Internet connection cut as a human rights infraction.

The conflict has been brewing since President Nicolas Sarkozy's government in 2009 set up the High Authority for Dissemination of Works and Protection of Rights on the Internet (Hadopi) to fight piracy and promote legal online sales.

Hadopi's procedure is this: they ask Internet service providers (ISPs) to hand over IP addresses -- a string of numbers that constitutes a fingerprint unique to a computer on a particular network -- being used for file sharing.

Suspects are then warned of the offence in an email, which says that legal action will follow if the piracy, usually over so-called peer-to-peer (P2P) networks, continues.

"Attention, your internet connection has been used to commit legally-noted acts that could constitute a breach of the law," begins the lengthy email. Piracy "is a serious threat to the economy of the cultural sector," it says.

If the piracy recurs within six months, the Internet user receives a second email, followed by a registered letter. After a third infraction, their Internet connection can be cut for up to a year and a fine imposed.

Measures have been taken to prevent those targetted from obtaining another Internet connection while suspended but the battle lines have been drawn and freedom-loving French are rising to the challenge of defeating Hadopi.

One chatroom user suggests sabotaging the system by only partially downloading files en masse -- thus creating millions of red herrings as a partial download cannot be viewed or listened to and is in theory not illegal.

Another site offers legal advice.

"You've received an email from Hadopi? The first thing to do is don't panic," advises the site's administrator, before explaining how to exploit what he says are procedural legal violations made by Hadopi.

Model letters can be downloaded for sending to Hadopi in response to their emails.

"13 ways to illegally download that Hadopi hasn't noticed" is the title of another page, suggesting using encrypted connections, server proxies, newsgroups and public wi-fi connections that cannot be traced to an individual.

There's even an online competition to see who can receive the first Hadopi warning by email.

Critics say that it is unfair to punish an entire family by cutting their connection just because a child in the household has downloaded copyrighted material.

Jack Guez, the head of French music producers' group SCPP which represents such big guns as EMI, Warner and Universal, highlighted the safeguards.

France's constitutional court had ruled that Internet access is not a human right, he pointed out.

But the court also said it was "a freedom of which one can only be deprived following a judge's decision," he said, voicing confidence that no music pirates would escape.

"The technology we use does not allow you to escape being detected while using a P2P network. Web users will quickly discover this."

And "contrary to what people think, Hadopi is able to cover all piracy technologies, not only P2P."

The music industry in France loses 700 million euros (almost a billion dollars) a year through piracy, he said.

But Tim Berners-Lee, the man credited with inventing the World Wide Web, warned last week of the "blight" of laws like Hadopi being introduced across the globe.

"There's been a rash of laws trying to give governments and internet service providers the right and the duty to disconnect people," he said in London, where a law similar to Hadopi was passed in April.

"If a French family can be forcibly disconnected from the internet by law for a year because one of their children downloaded something that some company asserts that they should not have downloaded, without trial -- I think that's a kind of inappropriate punishment," Berners-Lee said.

"I'd like to go on using the Internet. If it gets cut off, or for some reason things go wrong, in some cases, for me, my social life would disintegrate; for other people it may be access to medical information."

The US Senate is also considering a bill that would have the government create a blacklist of internet sites that US ISPs would be required to block.

So far, only those pirating music and films are being targeted in France, although representatives from the book and software industries are reportedly interested in joining the scheme.

Hadopi has been saying since April that it is about to start sending warning emails and last month announced the final countdown, with the first warning emails were sent out on Friday.