France plans to implement a tax on hepatitis C drugs in an effort to lower the high prices that the government of prime minister Francois Hollande believes threaten the country's healthcare budget.

The government has designed what it calls a "progressive contribution scheme" ensuring access for all patients to new and more effective treatments while limiting the burden of these drugs on state finances.

Unveiling the country's 2015 social security budget bill, health minister Marisol Touraine said the plans call for a tax to be levied on pharmaceutical companies when the total cost to the state from their hepatitis C drugs exceeds a certain amount each year, which would be €450 million euros in 2014.

Manufacturers would be taxed based on the revenue reaped in excess of that cap, which is expected to rise in 2015.

Details of the planned regulations are to be presented to lawmakers during October, with a vote on the budget due by the end of the year.

Some 200,000 people in France are believed to be infected with hepatitis C. Treatments for the virus could cost the state-run healthcare system as much as €1 billion this year, according to reports in newspapers Le Monde and Les Echos.

US biotechnology company Gilead obtained regulatory approval for its hepatitis C drug Sovaldi in Europe last January, but is still negotiating its official price in France, where it currently costs around €56,000 for 12 weeks of treatment, compared with $84,000 in the US.

According to forecasts compiled by Thomson Reuters Cortellis, Sovaldi is on track to be one of the world's biggest-selling drugs, set to rake in close to $12 billion in revenue in 2014, its first full year on the market.