Jacques Demy's 1967 musical, "The Young Girls of Rochefort", is a delight. Demy's previous musical film, "The Umbrellas of Cherbourg", from 1963, is actually an operatic melodrama with all the dialogue sung to musical accompaniment. "Rochefort" is a classic musical comedy with dialogue, singing and dancing. The cast of "Cherbourg" were chosen for their acting ability (and, in Catherine Deneuve's case, beauty). They weren't singers, but they sang on set and then their voices were completely replaced in post production by those of professional singers.
There are even more levels of artifice in "Rochefort". Deneuve and her sister Françoise Dorléac (the titular demoiselles) dance but the rest of the dancers are Americans, imported from Broadway and Hollywood. These include George Chakiris and, wait for it, Gene Kelly! The latter was in his middle 50s at this time but he could still bust some moves. The Americans' dialogue and singing were both replaced, although a few Gene Kelly lines in French seem to be his. The French actors just had their singing replaced.
The plot is completely goofy in a good way. Lovers are united and reunited. Like "Cherbourg", this film was shot on location in an Atlantic port town. The real locations make a great backdrop for the elaborate song and dance numbers and the wonderful 60s (pre-hippy) fashions. If 2012 is bumming you out, Travel back to 1967.