One of Paris's main thoroughfares, the Champs-Elysees, has been covered in earth and turned into a huge green space in an event staged by young French farmers.
They want to highlight their financial problems, caused by falling prices for agricultural produce.
Plants, trees and flowers were brought in by lorry overnight to transform the avenue into a long green strip.
More than a million people are expected to visit over the next two days.
The event, which cost 4.2m euros (£3.6m; $5.3m) to stage, has been organised by the French Young Farmers (Jeunes Agriculteurs) union over the holiday weekend in France.
It will serve as a showcase of farm production from sheep breeding to crop growing.
The union, which represents some 55,000 farmers under the age of 35, wants to impress on the public - and the government - the efforts required to produce what goes on the table.
"It's about re-establishing contact with the public about what our profession is and what they want from it," William Villeneuve, president of the Jeunes Agriculteurs, said on Friday.
"Do they want the cheapest products in the world or do they want products that pay producers?" he added.
Only in France are you ever likely to see such a monumental mobilisation of creativity and resources, all in the cause of that beloved but beleaguered figure: the French farmer, says the BBC's Hugh Schofield in Paris.
Overnight, 8,000 plots of earth have been brought into central Paris, and on Sunday morning, from the Arc de Triomphe down, the Champs-Elysees is one vast green space.
Some 150,000 plants have been installed - including 650 fully grown trees - representing agricultural produce from the marshes of the Camargue to the plains of Picardy, our correspondent adds.
Visitors will be able to buy boxes of the earth for their own gardens.