The 46-year-old was presented with the Chevalier des Arts et Lettres at the American film festival in Deauville from the country's culture minister Christine Albanel.
While giving away the honour, the minister praised Clooney's "limitless talent" and "irresistible charm," adding that he was the "quintessence of an American actor".
Meanwhile, Clooney has dismissed rumours that his recent weight loss is due to ill health, insisting he is simply on a diet.
Recent pictures of a super-thin Clooney relaxing near his beloved villa in the Italian lakes sparked speculation about the state of his health.
However, the actor and director put an end to the rumours by revealing the real reason for his new appearance - a range of faddish fitness regimes and a variety of work-out methods.