La Parisienne (1957)

The President of France's daughter falls for her father's attaché and asks to be his mistress. Instead he marries her and flies off on their honeymoon where she meets the prince who makes friends with her. This leads to a scandalous trip to Nice. Did something go wrong? They both come back with a cold. Is it from swimming or an assignation? The husband is jealous. What's the truth?