French rail workers began an open-ended strike over pension reforms tonight, the first step of a major challenge to President Nicolas Sarkozy's plans for economic reform.
Rail staff stopped work at 8.00pm and services are expected to be disrupted until at least the weekend.
With local transport workers in Paris and energy unions joining the rail workers on Wednesday, the strike could become the biggest France has witnessed in more than a decade.
Public servants are due to stop work in a separate dispute on November 20th.
Mr Sarkozy held last-minute talks with rail and utilities managements tonight but vowed to stand firm on his reform programme. "I will pursue these reforms to the end," he told the European Parliament. "Nothing will blow me off course."
Opinion polls suggest the public supports the president in his bid to reform a system that allows some public sector workers to retire on full pension after paying contributions for 2.5 years less than other workers.
But public worries over issues such as the cost of living and housing may fuel broader discontent if the dispute drags on.
Mr Sarkozy said the privileges were outdated and unfair to other workers, and they have become a test of his election pledge to break with the policies of the past and undertake a profound reform of the French economy.
State rail operator SNCF said it expected only 90 out of 700 high-speed intercity services to run during the strike. On the Paris metro, traffic will be "virtually zero" on all but two lines, while 10 per cent of the normal number of buses and trams are expected to run, the Paris transport authority said.
Further talks will be held tomorrow and the powerful CGT union made a late offer to soften its demand for one set of centralised talks between unions, employers and the government.
Prime Minister Francois Fillon said the government wanted to find a solution as quickly as possible. "We want negotiations that will prevent disruptions for transport users. This strike has to end as quickly as possible," he told TF1 television.
But commuters still face a repeat of the misery caused in a stoppage last month that disrupted the Paris metro system for days. Sympathy for the strikers has been far below what it was during the last battle over the special pensions in 1995.
Transport workers say their working conditions may not be as difficult as when their pension privileges, or "special regimes", were devised more than half a century ago, but say they still face awkward working hours that justify their status.
Introduced after World War Two for workers in especially arduous jobs, they allow some workers to retire after paying pension contributions for 37.5 years rather than the 40 years demanded of other workers.
The government says such schemes are outdated and costly, and it will have to pump €5 billion into the special pension funds this year alone to balance their accounts.