France's president proposed a sweeping new law on Thursday that would see repeat visitors to extremist web sites put behind bars - one of several tough measures floated in the wake of a murderous shooting spree.

The proposed rules, unveiled by Nicolas Sarkozy after the death of an Islamist fanatic wanted for a horrifying series of execution-style murders, have alarmed journalists and legal experts, who say they risk pulling the plug on free expression.

Sarkozy, who is only a month away from an election, argued that it was time to treat those who browse extremist websites the same way as those who consume child pornography.

"Anyone who regularly consults Internet sites which promote terror or hatred or violence will be sentenced to prison," he told a campaign rally in Strasbourg, in eastern France. "Don't tell me it's not possible. What is possible for pedophiles should be possible for trainee terrorists and their supporters, too."

French law calls for up to two years in prison and (EURO)30,000 (roughly $40,000) in fines for repeat visitors to child porn sites, although whether the proposed anti-terror rules would carry similar penalities isn't clear.

When asked, Sarkozy's office directed a query seeking details to the Ministry of Justice, which didn't immediately offer clarification.

Journalists and lawyers are concerned.

"Trying to criminalize a visit - a simple visit - to a website, that's something that seems disproportionate," said Lucie Morillon, who runs the new media bureau of journalists' watchdog group Reporters Without Borders.

"What's especially worrying for us is how you are going to know who's looking at what site. Does this announcement mean the installation of a global Internet surveillance system in France?"

Media lawyer Christophe Bigot seconded her concerns, saying that any such law - if passed - would be a serious blow to the democratic credentials of a country that considers itself the home of human rights.

"I don't see how you can assume that a person who connects (to an extremist website) not only shares the ideas that are being expressed there but is ready to act on them," Bigot said. "That seems to be a very dangerous shortcut - a real step back in terms of individual liberty."

Bigot said it wasn't clear to him to what degree Sarkozy's proposals were serious. In any case, France's Parliament isn't in session, but could be called back for urgent legislation. Otherwise, an eventual law would be contingent on Sarkozy's reelection.

The tightening presidential race has been upended by the shooting rampage blamed on Mohamed Merah, a 23-year-old Frenchman of Algerian descent who allegedly killed three French paratroopers, three Jewish schoolchildren and a rabbi before dying in a violent confrontation with police in the southern French city of Toulouse earlier on Thursday.

Sarkozy has France's far-right nipping at his heels, so he's been under pressure to appear tough. A poll released on Thursday by the CSA firm suggested that Sarkozy may benefit politically from a hardening of attitudes toward extremist violence.

Morillon said she understood the emotional appeal of a crackdown on online radicalization in the wake of such atrocities.

Still, she said, "you have to be careful not to attack the wrong target."

"Once more it's the Internet that's being blamed, as if the Internet was the source of all evil."