The French government has been accused of "Big Brother tactics" over a proposed anti-piracy law that aims to punish people who repeatedly illegally download music and films by cutting off their internet access for up to a year.

A bill is to be debated in parliament this week which could lead to a new surveillance agency to monitor internet users. With the help of internet service providers and tip-offs from music and film companies, those who illegally download music, films or video games would be identified. They would receive an email warning, followed by a letter, and if caught again would see their internet access cut off for up to a year.

The bill is a pet project of the president, Nicolas Sarkozy, who has taken advice from music and film industry leaders, who have warned that the country's creative industries are on their knees as a result of illegal downloading. The president's wife, the singer Carla Bruni, has long advocated a crackdown on piracy.

Christine Albanel, the culture minister, has said that France is "the world number one" in illegal downloading. An estimated 1bn pirated files were shared in the country in 2006. In a recent poll, 57% of 18- 24-year-olds admitted they had made illegal downloads and one in three French internet users admitted to online piracy. Music accounts for the biggest share of illegal downloading, followed by films, video games and American TV series.

Although the senate has passed the bill, a row over civil liberties is expected as parliament debates the law this week.

Christian Paul, a Socialist MP leading opposition to the law, said it would create a precedent for "massive surveillance" of the internet and society as a whole.

"Criminalising a whole generation is a dead end," he added, warning that the law would not bring an extra euro to crisis-hit record companies, which instead needed to look at their business plan. Socialists argue that the law, which focuses on file sharing or download sites rather than new technologies of streaming, is inconsistent and already outdated.

The consumer group UFC-Que Choisir called the law a "judicial monstrosity", warning it could cut off homes from the internet before they were given a chance to challenge the accusations. Several French blogs and websites, as well as groups on Second Life, have protested with black banners across their sites.

Frédéric Lefebvre, a spokesman for Sarkozy's ruling centre-right UMP party, said the law was about defending the "French cultural exception" and urgently protecting the nation's creative industries. The music industry has seen its market plunge by 50% in the past five years.

The proposed French law will go further than those of Germany or Britain.

An EU report last year argued that cutting off internet use was the wrong way to combat piracy. But the US, Ireland and Italy have taken measures to work with internet service providers to fight illegal downloading by suspending web access.