PARIS – France’s 35-hour workweek was cherished by workers but despised by many investors and employers. Now the bold social experiment has been dubbed a failure by France’s parliament.

The law gave many people more time for their families, for vacation, and for plain relaxation – but it fueled anxiety about declining competitiveness and soaring unemployment, currently at 10%. It also failed to live up to its original promise: creating millions of jobs by forcing employers to hire more people.

The conservative-dominated National Assembly, France’s lower house, voted overwhelmingly Tuesday to adopt a government-backed bill that significantly waters down the 35-hour week legislation, a legacy of the former socialist administration. It opens the door for companies to increase employees’ working time in exchange for better pay.

President Chirac’s government has tried to sell the reform to voters as an opportunity to “Work More to Earn More,” but many remain unconvinced.

Almost 1 million people joined strikes and demonstrations earlier this month to defend the 35-hour week and protest other perceived threats to their working conditions and pay. The antipathy could spill over into a May referendum on the new E.U. constitution, in which the government is campaigning for a ‘yes’ vote.

The new law endorses an increase in the extra hours employees can work to 220 every year from the previous limit of 180. It also allows them to go further with “optional overtime” in return for extra pay and lets them sell part of their holiday entitlement back to their employers or put it toward early retirement, training or sabbatical leave.

But trade unions doubt that the extra time will be quite as optional as promised – especially for people working in small companies.

“Officially they can say no. In practice it’s less certain,” said Remi Jouan, national secretary of the CFDT, France’s largest union.

“It won’t be the employee that chooses, it’s the employer that decides whether there’s work or not.”

Mr. Jouan believes the main impact of the reform will be felt when, or if, France’s economy picks up and companies choose to increase hours instead of hiring. “That’s our problem with this reform,” he said. “It’s just not an answer to unemployment.”