French unions have called two more national days of action to protest at the government's pension reforms.
They announced the dates of 28 October and 6 November after a meeting in Paris.
Separately, rolling strikes are continuing against government plans to raise the pension age from 60 to 62.
President Nicolas Sarkozy has tabled a motion to cut short debate in the Senate, forcing an emergency vote within 24 hours.
Opposition senators had prolonged the debate by putting forward more than 1,000 amendments.
Riot police in body armour are in position outside the French Senate, reports the BBC's Phil Mackie in Paris.
The lower house has already approved the bill, which aims to raise the retirement age from 60 to 62 and the full state pension age from 65 to 67.
Economy 'taken hostage'
Protests have taken place around the country. In the south-eastern city of Lyon, police used water cannon to disperse protesters.
A demonstration outside the Senate in Paris was largely peaceful.
"I am 44 and I don't want to work until I am 62 or 67," teacher Odile Jaquet told the Associated Press news agency. "I am still young: I still have to work for another 18 years, and in my industry, I don't think that I will be able to work much longer."
Students marched in cities around the country including Paris, Marseille, Toulouse and Bordeaux.
In Marseille, tonnes of rubbish have piled up in the streets since collectors went on strike on 12 October.
The top central government official in the region, Michel Sappin, has asked 150 members of the civil security force and the French Foreign Legion to clear the rubbish.
Blockades of refineries and fuel depots have led to fuel shortages. Ecology Minister Jean-Louis Borloo said 2,790 filling stations had run out of fuel, down from 3,190 on Wednesday.
However, about three quarters of high-speed TGV trains are now running, as are about half of all regional trains.
President Sarkozy called for an end to the disruption and promised to punish rioters.
"By taking hostage the economy, companies and the daily lives of French people, we are going to destroy jobs," he said on Thursday.
Lionel Guerin, head of the National Federation of Commercial Aviation, said the strikes had now cost airlines more than the Icelandic volcano eruption in the spring.
Singer Lady Gaga said on her website that she had cancelled two concerts scheduled for Paris this weekend because was "no certainty that the trucks can make it" to the venue.
All 12 French refineries remain on strike, although police have broken blockades at most of the country's fuel depots.
Strikes also stopped work at two of France's three liquefied natural gas (LNG) terminals.
On Wednesday, the country began importing electricity as the wave of protest action took hold of energy supplies.
At least 12 of France's 58 nuclear reactors were shut for maintenance, but the unions say production has been cut at four others.