Hundreds of protesters wearing the traditional red headgear symbolizing Breton resistance to the tax policies of the Socialist-led government of President Francois Hollande clashed with police in Brech, about 300 miles west of Paris, the daily Ouest-France reported.
Three protesters and a French gendarme were injured and three were arrested during the confrontation amid heavy gale conditions along the RN 165 highway, which was closed by police as a preventative measure.
Red cap organizers said up to 1,000 people turned out to protest the government's proposed environmental tax on trucks and heavy vehicles, while police put the number at 250.
Protesters marched along the highway from Landaul, France, toward an automated tax collection station in Brech -- several of which had been destroyed by protesters in previous disturbances. About 200 yards from the site, gendarmes blocked access to the station and a tense standoff developed, the newspaper said.
Demonstrators threw eggs at riot police, who responded by firing tear gas canisters, producing thick smoke. The clashes continued for another 30 minutes before protesters dispersed by 6:30 p.m.
The red caps had announced on their Facebook page last week they wanted to hold a peaceful event, planning what they called a picnic with speeches, but Thierry Merret, president of the Breton famers union FDSEA du Finistere, told Le Figaro the police actions provoked an angry reaction.
"We wanted it to be peaceful, but as the police prevented people from approaching, and it has upset everyone," he said. "We hope that the government has realized that the red cap movement is far from faltering."
He said the demonstrators didn't appreciate recent statements by French Transport Minister Frederic Cuvillier, who said this month he wanted to see the eco-tax begin sometime in 2014 after plans to launch it starting Jan. 1 were suspended in October following a series of violent red cap protests.
The eco-tax, introduced by the previous government of President Nicolas Sarkozy and passed with cross-party support, is meant to raise $1.57 billion as a way to boost freight by rail or other eco-friendly alternatives to trucking, Radio France International reported.
Opponents, however, claim the measure will have dire consequences for farming and the food processing industry in Brittany, where they say some 8,000 jobs have been lost in two years as a result of globalization.
They are worried that the trucking companies will pass on the tax along to consumers, further hurting the Breton economy.
Merret said the the protesters are now looking forward to a March 8 all-Brittany congress in Morlaix -- the hometown of French Minister of Decentralization Marylise Lebranchu -- which will formally take up Breton grievances collected through 50 local committees of the red caps.