French President Nicolas Sarkozy and first lady Carla Bruni arrive at the Kurhaus in Baden-Baden, Germany, for a NATO function in this April 3 file photo. Sarkozy has pushed an unprecedented law to cut the Internet connections of people who repeatedly pirate music and movies, but many are concerned about its ramifications on privacy.

Paris ? A thousand French Internet users a day could be taken off-line following approval of President Nicolas Sarkozy’s pet project — an unprecedented law to cut the Internet connections of people who repeatedly pirate music and movies.

As the husband of supermodel-turned-pop star Carla Bruni and friend to some of France’s most powerful media figures, Sarkozy has long basked in his cozy ties with the entertainment industry, which has embraced the measure.

But many in Europe have denounced it, saying government controls needed to enforce the law could open the way for invasive state monitoring that violate privacy. And legal challenges at home could derail it: The opposition is trying to get the law declared unconstitutional.

Predictably, music, film and other industry groups have welcomed the measure. John Kennedy, chairman and CEO of the International Federation of the Phonographic Industry, said Wednesday that it represents a “sea change.”

Critics, however, worry about civil liberties.

“We should be careful about interfering with the freedom of exchange of information,” said Wolfgang Zankl, professor at the University of Vienna and president of the European Center for E-Commerce. “This is a constitutional right which no one should be barred from.”

Some Internet experts say the law will be technically impossible to apply. It requires Internet subscribers to install special software that would enable authorities to track down and identify those suspected of illegal downloads, but some experts say such programs do not yet exist.

And because it denies accused pirates the chance to defend themselves before their Web connections are severed, legal experts say it will not stand up in court.

The measure’s first short-term test came Tuesday, when the opposition Socialists took their objections before the Constitutional Council, which has a month to issue a ruling. If the council decides the law does not violate the constitution, it could take effect by summer.

It calls for graduated reprisals against alleged offenders. If a suspected pirate fails to heed e-mail warnings and a certified letter, Internet access would be cut for two months to a year — with the subscriber required to keep paying for the service under the contract’s terms.

Christine Albanel, the French culture minister, foresees cutting 1,000 Internet connections a day and sending 13,000 warnings to first- or second-time offenders.

In the United States, the music industry has waged war on content swappers with limited success. A campaign to sue individuals who repeatedly download free songs was dropped last year in favor of an effort to work more closely with Internet service providers to try to block connections of alleged offenders. AT&T, the largest Internet service provider in the U.S., is beginning to send the warnings to its subscribers.

Even before the French legislation was approved this month, it encountered resistance in the European Parliament. Elections for a new parliament take place in June, and the fight for Internet freedom has become a campaign issue in some countries, notably Sweden, which has gained a reputation as a hub for illegal file-sharing.

Support for Sweden’s Pirate Party, which calls for legalization of file-sharing, is growing, and a recent poll shows the party could gain a seat in the European Parliament.

Christian Engstrom, the party’s nominee, said the French law is damaging to the free exchange of information on the Internet. French cooperation with the “greedy copyright industry is not fitting for a Western democracy,” he said.

With the exception of Sweden, where a court sentenced four men last month to one-year jail terms for helping people download copyrighted material, court cases in Europe have failed to dent the practice. A Spanish court this week will hear the latest industry case against suspected file-sharers.

Russia and Ukraine are some of Europe’s biggest offenders in illegal file-sharing. However, they have no intention of passing legislation similar to that in France and are out of the reach of eventual European Union rules.