The Monegasque monarch, 65, attended the ceremony at the Grimaldi Forum in Monte Carlo and hailed Ranier III for founding the pioneering festival in 1961.
The night before at Sinatra’s Tamarisk Country Club home there had been a party to celebrate the silver wedding anniversary of Princess Grace and Prince Rainier.
The European royal, 64, attended the 45th International Circus Festival in Monte Carlo with his twins, niece and nephew over the weekend, following its grand opening last week .
The European royal, 57, got stuck into the celebrations in Monte-Carlo and happily posed for photos while an impeccably trained parrot perched on her shoulder.