French workers are divided over whether to stay at home on what used to be the Pentecost public holiday.
French train services are expected to run holiday timetables
About 50% - mainly state employees - stayed at home on Monday, despite the fact that the government scrapped the holiday in 2004.
France cancelled the day off to help fund healthcare for the elderly and disabled people, following the deaths of 15,000 in a heatwave in 2003.
The government said the extra day was needed to help fund social programmes.
The idea was to ask people to work the National Day of Solidarity, as the government called it, to help pensioners and the disabled - those most affected by the hot summer. At first the principle was widely accepted.
The government raised 2.2bn euros (£1.5bn) from the holiday last year and hopes to do the same in 2006, to help hire nursing staff and expand residential home provision.
But the "compulsory labour day", as some critics have called it, proved unpopular last year.
The BBC's Caroline Wyatt in Paris says it is still causing confusion and chaos as around half the country continues to take the day off as holiday, while the other half works.
She says there is resentment because it is mainly government employees who are taking the day off: schools are closed, for example, making it difficult for parents to go to work without arranging extra child care.
'Room for improvement'
Post offices and many government ministries are also shut. Public transport is in holiday mode: the SNCF railway came to a novel agreement with its workers, who said they would work an extra two minutes or so per day for the rest of the year to make today a holiday.
Others are using up the days off gained as part of their 35-hour working week, while a handful of private companies are paying into a solidarity fund on behalf of their employees, and giving them the day off.
Our correspondent says that all in all, the well-intentioned idea has proved chaotic in the extreme, prompting criticism from employers and unions alike.
Speaking from a work trip to Finland, even French Prime Minister Dominique de Villepin admitted there was some room for improvement in the way France approached this day of solidarity.