French farmers are in debt and are facing difficulties as food prices have fallen from record highs in 2007.
The agriculture ministry said this week that farmers' revenues fell 34 per cent in 2009.
President Sarkozy pledged in October to provide $1.5bn in bank loans and other aid measures for cash-strapped farmers.
Farmers say they are not satisfied and have denounced deregulation of the European agricultural markets, accusing Sarkozy of scorning them.
Damien Gressin, from the Young Farmers union, said: "Do you (Sarkozy) think we are so gullible as to believe your promises?"
He demanded France to press for greater market regulation and for the government to take a new look at 2010 subsidies to take into account falling prices.
France is the largest farming economy in the 27-member European Union.
It is the biggest beneficiary of subsidies under the EU's Common Agricultural Policy (CAP), reaping more than $14 billion in annual aid.
But the EU Commission is considering an overhaul of the bloc's budget that would shift spending away from agriculture towards innovation, a move France opposes.
In an interview on France Inter radio, Bruno Le Maire, France's agriculture minister, said he understood the farmers' anguish.
"When you wake up every day, even if you work 12 to 14 hours, and know you are going to lose money at the end of the day, there is indeed something to be upset about," Le Maire said.
He called for measures to stabilise prices but did not specify what those might be.
In October, Le Maire recommended that Sarkozy reduce the tax burden on farmers this year.
Grain farmers, milk farmers and sheep farmers are among agricultural workers who have held protests recently in Paris.