Hundreds of furious farmers have blocked access roads to France's second city Lyon with their tractors, unimpressed with a 600-million-euro government plan to ease their dire financial plight.
Faced with a growing political crisis, President Francois Hollande added to his Thursday schedule an impromptu visit to the eastern city of Dijon to meet officials from top agricultural unions.
For several weeks, farmers have blocked access to cities, ports and even the tourist hotspot of Mont St Michel to highlight their situation, with many saying they are on the brink of bankruptcy.
A combination of factors, including changing dietary habits, slowing Chinese demand and a Russian embargo on Western products over Ukraine, has pushed down prices for staples like beef, pork and milk.
Acutely aware of the power of the agricultural lobby in France, the government reacted on Wednesday with an emergency package worth 600 million euros ($A890 million) in tax relief and loan guarantees.
But the packages appeared to fall short of expectations and while some blockading farmers did stop their action, others stepped up their protest.
Farmers stationed tractors on the key roads into Lyon, vowing to block or slow access to the southern city until at least Thursday night.
The main FNSEA farmers' union dismissed the package as "insufficient", saying it provided only a short-term sticking plaster, not a long-term structural solution to the industry's problems.
Speaking on French radio early on Thursday, Prime Minister Manuel Valls said it was "essential that prices rise in the beef market".
He called on "everyone to live up to their responsibilities", singling out the abattoirs and food processing industries, which farmers blame for keeping prices low.