Pinning a red-ribboned medal to Redford's blue suit, Sarkozy made him a knight in the Legion of Honor.
Redford thanked the French people, recalling the time he spent in France after dropping out of college.
"I didn't know anything about my own country, I was naive and narrow-minded and it was the French students ... who opened my eyes and gave me a real education," said Redford.
Napoleon Bonaparte created the legion in 1802. It recognizes military, cultural, scientific or social contributions to France, including by people who are not French citizens.
The Associated Press contributed to this report.