Police and demonstrators demanding jobs and a definitive end to a road tax on heavy vehicles skirmished ahead of a protest march by at least 10,000 people in western France.
Protesters threw stones at police who responded with water cannons and tear gas ahead of Saturday's march in the city of Quimper in the Brittany region.
France's government suspended the "eco-tax" after violent protests last week in which a man lost an arm in the clash.
Agriculture is a leading industry in the region and it has been hard hit by the economic crisis. It depends heavily on trucks to transport goods. Protesters want the tax killed.