"(Ah, the Apple Trees) When the World Was Young" is a popular song composed by Philippe-Gérard [fr], with lyrics by Angèle Vannier [fr].
The original French title was "Le Chevalier de Paris".
Apart from a reference to apples, the English lyrics only have minor commonalities with the original French words.
English lyrics were originally written by Carl Sigman, but these were rejected by the music publisher, Mickey Goldsen.
[1] The song is from the perspective of an aging Parisian "boulevardier"/"coquette", as they review their life.