The French government has used the security forces to lift blockades by strikers at three fuel depots serving the west of the country.
President Nicolas Sarkozy has authorised police to break all remaining blockades at fuel depots.
French workers are taking their rolling strike against planned pension reforms into its seventh day.
Student leaders have also called for more protests ahead of a senate vote on the retirement age later this week.
Transport workers said they would continue their protest on Wednesday but the national rail operator, the SNCF said at least half of its trains will run on Wednesday, with up to two thirds of high-speed TGV trains running on schedule.
Mr Sarkozy has insisted he will press ahead with plans to raise the retirement age from 60 to 62 and the full state pension age from 65 to 67.
Across the country, one in three fuel stations has run dry. All 12 refineries on the French mainland have been affected by strike action.
French interior minister Brice Hortefeux authorised use of the paramilitary police to break blockades at fuel depots. He said he respected the right to protest, but that did not include the right to block workers or to commit pillage or violence.
The BBC's Christian Fraser said this force was the equivalent of a Swat team whose normal duties include hostage rescue.
Overnight, riot police lifted the blockade at three fuel depots, in Donges, La Rochelle and Le Mans. However, strikers reimposed their blockade at Donges in the early hours of the morning.
In the south of the country, unions have blocked the fuel depot at Trapil, which supplies civilian and military airports in the region.
Our correspondent said the unions and the government were engaging in a game of cat-and-mouse over the fuel blockades.
For the second day running, cars were overturned and set alight in Lyon. There were also disturbances in Mulhouse and Montbeliard in eastern France.
Mr Hortefeux has condemned the violence in the suburbs, saying it was "unacceptable" that more than 60 police officers had been injured.
On Tuesday, unions called a sixth national day of protest since the return from the summer holidays in September.
About 1.1 million people took to the streets, the interior ministry said; the CGT union put the number at 3.5m.
The numbers were comparable with the previous week's national day of action.
Tuesday's day of action was seen as a last attempt to mobilise protesters before the Senate's final vote on the government's pension reforms later this week. The lower house, the National Assembly has already approved the package.
The BBC's Gavin Hewitt, in Paris, said that union leaders had to decide how to keep up pressure on the government.
The planned increases in the retirement age are widely unpopular in France.
But the unions are wary about public reaction to long queues at petrol stations, our correspondent said.
Education has also been affected. Officials said 379 secondary schools were either blockaded by pupils or had suffered some disruption on Tuesday, the highest number since the protests began in early September.
In some areas, schools became a focus for violence. Outside a secondary school in the Paris suburb of Nanterre, youths threw stones at police who responded with tear gas.
Despite the widespread disruption, the strikers continue to attract popular support, with one opinion poll suggesting that 71% of those surveyed back the industrial action.
President Sarkozy's poll ratings appear to have dropped even further as he tries to tackle the wave of protests.
One poll for BVA conducted on 15 and 16 October suggested his approval rating was down to 30%, the lowest for three years.
The number of French with either a negative or very negative opinion of their president rose five points from September to 69%.