PARIS: French farmers dumped flour over the stand of a leading meat producer at the country's annual farm show Sunday, a day after they heckled President Francois Hollande as he arrived at the event.

The farmers' anger has boiled over after months of protests over a crisis in the agricultural sector sparked by collapsing beef, pork and milk sales and augmented by a price war with wholesalers.

The upset, which has seen farmers leave their fields and animals to block roads with their tractors and dump manure outside government offices, has also cast a pall on the country's biggest celebration of its agricultural wealth.

On Saturday, farmers tore down the agriculture ministry's pavilion, resulting in the arrest of five members of the main farmers' union FNSEA.

And despite calls for calm, the protests continued when a group of farmers attacked a stand owned by one of France's biggest agri-businesses.