The belly of Paris is a story of wealth and poverty amidst a sumptuous banquet of food and commerce. Having just escaped from prison, young Florent arrives in Paris' food market, Les Halles, half-starved, surrounded by all he can't have and indignant at his world, which he now knows to be unjust. Gradually, he takes up with the local Socialists, who are more at home in bars than on the revolutionary streets.