Monday is the 12th day of a transport strike in France.
The strike was mounted in protest of the government's desire to overhaul the country's more than 40 pension schemes into a single universal system for everyone.
The overhaul would include raising the retirement age from 62 to 64. Pensions would be based on the earnings throughout the worker's career, as opposed to the current system that bases pension payments on the worker's highest income.
Prime Minister Edouard Philippe said the changes would ensure the pension system is "fair and sustainable" in the face of a growing population.
Union leaders, including Philippe Martinez, the head of the prominent CGT workers union, have flatly rejected the new plans. "The government is making fun of everyone," Martinez said.
Unions are planning mass demonstrations for Tuesday.
The strike has clogged Paris since most metro lines have closed and few commuter trains are running. It has also disrupted domestic and international train and airline service.
The strike could destroy holiday plans. It would be "irresponsible" of union leaders to "ruin vacations," Environment Minister Elisabeth Born told France 2 television.
Rail operator SNCF has warned that it is possible that rail service will not be back to normal by Christmas if the strike does not end in a few days.