Paris: French rail workers walked off their jobs on Wednesday to kick off 24 hours of nationwide strikes and protests called by the country’s main unions to denounce President Nicolas Sarkozy’s handling of the economy.

Up to 2.5 million people took to the streets on a first such day of action on 29 January and union leaders hope even more demonstrators turn out at some 200 rallies planned for Thursday.

Opinion polls say around 75% of voters back the protest movement, posing Sarkozy’s toughest challenge since he took office in May 2007.

The unions have presented a shopping list of demands, including a boost to poorer paid salaries, more measures to protect employment, a tax hike for high earners and a halt to planned job cuts in the public sector.

“A very strong sense of injustice is building up,” Jean-Claude Mailly, head of the Force Ouvriere Union, told Reuters. “I think the government will find it hard to ignore us. That would be irresponsible.”

The government has introduced a €26 billion ($34 billion) stimulus plan aimed at investment and after the 29 January strike Sarkozy offered up to €2.65 billion of additional aid, primarily to help vulnerable households weather the storm.

Ministers say there will be no further concessions, explaining that the previous measures have not properly taken effect and warning that heavily-indebted state accounts cannot afford any more generous handouts.

But in the light of global economic recession Sarkozy is clearly concerned about growing social tensions in France, which has a culture of street protests, with bush fires flaring up across the political landscape.

French students threw bottles at police and broke shop windows in Paris overnight during an unauthorised demonstration in an ongoing dispute against a planned university reform.

Police are also reporting regular skirmishes with youths in the poor, high-rise suburbs around Paris that were the epicentre of three weeks of nationwide rioting that shook France in 2005.

The union protests started at 8 pm (1900 GMT) on transport networks, with the national rail company SNCF predicting that 40% of high speed trains would be cancelled and up to 60% of local train traffic.

Airports, schools, buses, government offices and some private companies will also be hit on Thursday, but as in January, the country is not expected to grind to a halt.

With its large public sector and generous welfare system, France is better placed than many to ride out the economic storm, but it is nonetheless taking a hit, with many analysts predicting that the economy will contract by 2 percent this year and unemployment jump 25% to almost 10%.

The crisis has already forced Sarkozy to water down his domestic reform agenda and he is facing pressure to undo some of his original moves, including a “fiscal shield” that allowed the rich to pay no more than 50% of their income on taxes.

Sarkozy is refusing to budge, but unions are confident the government will eventually give in to many of their demands.

Earlier this year, the government initially refused to move during a general strike on the French Caribbean island of Guadeloupe, but after a six-week stand off it finally caved in and agreed to a €200 hike in minimum monthly wages.