A 24-hour national strike is taking place in France, in what is seen as the biggest challenge yet to the centre-right government of Prime Minister Jean-Pierre Raffarin.
Most transport services have been withdrawn
Planes, trains and buses ground to a halt, schools were shut and newspapers failed to appear on the stands as public sector workers stayed at home in protest at Mr Raffarin's plan to reform the country's pension system.
Hospitals and post offices are also affected, as are public utilities such as gas and electricity.
Demonstrations are taking place across the country, with tens of thousands gathering in Paris for protest marches.
Mr Raffarin says his plans to make employees pay more over a longer period towards their pensions are urgently required in order to shore up a growing deficit.
The shortfall, which has mounted as the "baby boomers" generation goes into retirement, is expected to reach 50bn euros (£36bn; $57.4bn) by 2020.
The unions agree that the disproportionate ratio of workers to pensioners is a problem, but insist there are other ways of finding the money.
Their strike co-incides with a mass walkout by teachers in Austria, part of a series of major protests against the Vienna government's plans to reform pensions.
Last week the country saw the first national strike in more than half a century as unions mobilised against the planned reforms.
Parisians walked, cycled and skated to work on Tuesday morning, as the metro all but shut down.
State workers must pay in for 40 years to receive full pension -matching private sector - by 2008
Payment period to be increased to 42 years by 2020
Higher contributions from 2008
Workers to be allowed to stay on after official retirement age
Tax incentives introduced to boost company-based savings schemes
Train and bus services across the country have been hit, and some 80% of international and domestic flights have been cancelled at French airports.
The Eurostar service to London and Brussels will be unaffected, the state-owned SNCF said, but sea ports are likely to be closed for at least part of the day.
Crippling transport strikes in 1995 forced the government to retreat from its attempts at pension reform - and it lost an election two years later - but Mr Raffarin has insisted that he will not let his government be intimidated by the protesters.
Mr Raffarin said in an open letter to the French people that he is determined to push the measures through parliament, warning that if nothing was done to deal with the problem of an ageing population, then in 20 years pensions would be halved.
Union leader Marc Blondel has declared however that the prime minister should listen to his electorate.
"If people are discontented, it should be possible to get the upper hand and secure a withdrawal of the proposals," he told the newspaper Le Journal du Dimanche at the weekend.
On Monday, the three main union federations were boosted by two opinion polls that indicated a majority of French people
were sympathetic to the cause of the protests.