PARIS — Tens of thousands of French workers staged nationwide protests yesterday against plans by President Sarkozy to make people work a year longer to qualify for a full pension.

France’s five largest unions joined forces to fight a government proposal obliging employees to work 41 years before retiring, against 40 years at present. They are also angry at plans to cut the numbers of public sector workers.

Half the country’s trains were not running, but the action had less impact on public transportation than expected because of a new rule on securing a minimum service during strikes. Paris and Lyon were barely affected and there were no delays on international routes.

Union leaders insisted that success should be measured by the turnout at rallies, not strike numbers, saying 700,000 people took part in 153 towns and cities. Police figures were far lower.

Given the scale of the protests, the government must “review its plans under pressure,” said Bernard Thibault, the head of the militant CGT union, which represents public service workers.

Prime Minister Fillon said there was no alternative but to increase the number of working years in line with rising life expectancy.

The president has cause for quiet confidence, judging by one poll cited by the newspaper Le Figaro, in which almost six out of 10 French people oppose the protests — the latest sign that despite his current unpopularity, Mr. Sarkozy appears to be winning the ideological battle for his reforms. In a boisterous mood, according to Le Figaro, the president predicted to one close adviser that “one day they’ll say I made as many reforms as Margaret Thatcher!”