But there were some indications that the walkout was losing a little momentum, even as strikers voted to keep going through the weekend.
Fewer than one-third of train drivers stayed off the job Friday, down from 60 percent in the first full day of walkouts on Wednesday.
Several unions for both the national rail operator, SNCF, and the Paris transit authority RATP agreed to press on with the strike through Monday, labor officials told The Associated Press.
Unions called the walkout to protest Sarkozy's plans to strip away generous pension benefits for train drivers and some other state-run sectors. Sarkozy's image as a reformer depends on him not caving into the pressure.
SNCF executive Guillaume Pepy said Friday that "some uncontrollable strikers or outside elements" were blocking trains by setting fires or setting off firecrackers. He called such unrest "scandalous and absolutely unacceptable."