Farmers on their tractors have been descending -- slowly -- on the capital from all corners of France, angry over the falling food prices which they blame on foreign competition, Russian sanctions, and a raw deal from local supermarkets and distributors.

It has taken many of them a week to reach the capital, travelling at an average speed of 35 kilometres (22 miles) an hour.

"What we're asking for today is three or four centimes more on a burger," said Xavier Beulin, head of France's leading farmers' union FNSEA, told iTele.

The first tractors to arrive came from the northwestern region of Brittany, a major producer of milk and pork.