French riot police fired tear gas Tuesday at hundreds of protesters trying to storm a Paris auto show, during nationwide protests over mounting job losses in a moribund economy with 10 percent unemployment.

Thousands of other demonstrators marched in Lyon, while operations the ports of Le Havre and Marseille were disrupted.

The protests, organized by a national confederation of trade unions, came as the number of French unemployed topped three million for the first time in 13 years. CGT Union leader Bernard Thibault, who openly called for the defeat of former President Nicolas Sarkozy, says the economy has not improved since Socialist President Francois Hollande took office last year.

Mr. Hollande campaigned against international demands to cut public spending with tactics he said unfairly targeted workers. Analysts say he is now caught between those cost-cutting demands, and those of his core union supporters.

Unions were also protesting Tuesday's ratification by the French parliament of a European fiscal treaty that stiffens penalties for countries that overspend.

A key poll published last week in Figaro Magazine showed Mr. Hollande's support tumbling to 41 percent — a record low for a president six months into his tenure. The same TNS-Sofres survey showed support for Prime Minister Jean-Marc Ayrault dropping 10 points to 41 percent.