The French government scrambled Tuesday to contain anger over a proposed environmental tax as protesters continued to destroy radars set up to help collect the levy, in a revolt that shows no sign of abating.

Protests over the new "ecotax" on trucks, which aims to encourage environmentally friendly commercial transport, kicked off in earnest last month in the northwestern region of Brittany and eventually forced the government to backtrack and suspend the levy.

Wearing red bonnets, the symbol of a 17th-century anti-tax campaign in Brittany, the protesters -- small business owners, fishermen and food industry workers -- marched in big, sometimes violent, rallies in the region, which has already been crushed by job cuts and would be hard hit by the new tax.

Some destroyed radars set up in advance along roads to screen passing vehicles and determine whether they need to pay the tax, which would apply to French and foreign vehicles carrying goods weighing over 3.5 tonnes.

Under pressure to rein in its state deficit, France's Socialist government has announced about 3 billion euros ($4.1 billion) in tax increases for next year, and protests in Brittany come on top of wider opposition to tax hikes.

The ecotax was actually adopted by the previous right-wing UMP government in 2009 but its implementation had repeatedly been put off.

And while the Socialist government suspended the levy last week over the unrest, protesters asking for the tax to be completely abandoned have continued to destroy radars, mostly in Brittany but in other parts of the country too.

On Tuesday, the transport ministry said 11 such radars had been vandalised since the beginning of the protest movement, as had four big overhead road structures equipped with cameras and radio receptors.

This equipment would identify trucks liable for the tax thanks to a GPS box installed inside the vehicles.

Controversy has also started to swirl around Ecomouv', the firm contracted by the previous government to collect the tax, amid "questions" over how the company was awarded the contract.

Finance Minister Pierre Moscovici on Tuesday said the contract signed with the firm -- which is majority owned by Italian company Autostrade per l'Italia -- would have to be renegotiated.

"We can question the fact that the collection of a national tax was handed over to a supplier with foreign origins," he said.

And while protests have so far been concentrated in Brittany, there is concern that the unrest may spread to other parts of France.

Last week, market gardeners staged a rally in a region near Brittany to demand an end to the levy, and several ecotax radars have been destroyed in other parts of France.

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