Paris ? Strikers shut down much of France’s national rail service after rush hour Tuesday night, and millions of Paris commuters prepared to go without subways when the city’s train crews join the walkout.

People planned to use the capital’s new bicycle rental service, share cars or stay home during today’s subway strike. Others said they would walk.

Xavier Basset, an accountant, faced a nearly four-mile walk across Paris to his office. “I’ll work on my calves,” he said.

Unlike recent limited transportation strikes, rail unions set no time limit for the shutdown called to protest the conservative government’s move to eliminate special rules that allow train drivers and certain other public workers to retire early.

President Nicolas Sarkozy’s government insists the pension rules are outdated, unfair and too costly. Several opinion surveys suggest Sarkozy has public support. He vowed Tuesday not to give in to trade unions, which have defeated previous government attempts to loosen work rules.