How was Gérard Debreu awarded the Noble Prize in Economics?

Name: Gérard Debreu.
Country: France.
Date of Birth: July 04, 1921.
Died: December 31, 2004.
Education: Graduate from École Normale Supérieure and Doctor of Philosophy (Ph.D.) from the University of Paris.
Subjects Of Study: Econometrics equilibrium.
Popularly Known: The Theory of Value: An Axiomatic Analysis of Economic Equilibrium.
Noble Prize Year: Nobel Prize for Peace in 1983, for his fundamental contribution to the theory of general equilibrium.