France has pushed through a presidential decree that forces internet providers in the country to block access to sites that incite or advocate terrorism, following the murders of editorial staff at satiricial publication Charlie Hebdo and the bloody aftermath of the attack.
Sites that carry paedophilia content must also be blocked, the decree issued by French president François Hollande and six senior ministers including prime minister Manuel Valls demand.
A list compiled by the French Ministry of the Interior of offending sites will be the final authority that ISPs must use to block access for their customers, the decree said.
ISPs are barred from altering the list in any way, or deleting entries on it. They are also required by the government to keep the list secret, the decree ordered.
Providers can however invoice the French government if they incur additional operational costs in implementing the site blocking.
Although the decree does not go into deep technical detail, the address list use either fully-qualified domain names (FQDNs) for the site, or host names for server operators.
Internet censorship through blocking of websites deemed to carry offensive content is increasingly finding favour with governments around the world.
Britain has operated a filtering system that requires internet users to opt-in if they wish to view sexual content since last year. It has been criticised for blocking several legitimate sites such as Linuxtracker.org which provides links to Linux distributions and other free, open source operating system downloads.
Australia's web blocking under Section 313 of the Telecommunications Act came under fire in 2013 after the securities and investment commission accidentally blackballed a quarter of a million sites in an effort to prevent access to just 1200.
To prevent such mistakes in the future, the communications department issued guidelines for government departments that want websites blocked, a move that was supported by the Australian Federal Police.
The French presidential decree came into effect upon publication on Friday February 6. It also applies to France's Pacific territories New Caledonia, French Polynesia and the Wallis and Futuna Islands.