French farmers are threatening to step up a series of mass blockades in response to falling prices they say are driving them to the point of bankruptcy.
Farmers have dumped manure in cities, blocked access roads and motorways and hindered tourists from reaching Mont St Michel, one of the country's most visited attractions.
Overnight on Tuesday (local time), they blocked the A1 motorway, a key artery between Paris and northern France, using about 500 tractors.
The head of the powerful FNSEA farmers' union, Xavier Beulin, said he expected the protests to continue, adding they "could be extended to other regions on Wednesday".
Jean-Pierre Fleury, head of a union representing beef farmers, said: "The farmers will not let up, for the simple reason they are fighting for their lives."
A combination of changing dietary habits – French consumers are eating less meat – and foreign competition has driven down pork, beef and milk prices.
Farmers blame supermarkets, distributors and the food processing industry for keeping prices low.
Retailers and food industry chiefs had promised to raise prices on meat and dairy after a meeting with farmers last month but the farmers say price hikes in supermarkets are yet to filter down to them.
Stung into action, French President Francois Hollande has promised to unveil an emergency plan.
Agriculture Minister Stephane Le Foll has already hinted measures could include tax breaks and debt relief for heavily-indebted farms.