It's interesting how quality is just quality. It doesn't matter that you might be a millennial watching this film from France, from the 50's, it's just as good as any more contemporary or culturally relevant top drawer picture.
The best feature in this is efficiency. It's short and sweet (just about 1hr20min), no scene ever stalls the movie, no line in the dialogue branches out into its own thing. It's tight, focused, and efficient. It knows exactly what it's about.
It's both fantastical in its concept and terribly realistic at the same time. Both lead actors were perfect for the cast and play their roles perfectly, while Louis de Funes is also excellent in a more secondary but not any more quiet role.
The film dishes out bits of life lessons here and there, forces a bit of thought and perspective, but never feels self-complacent or happy about itself. It delivers the goods, with a super simplistic plot, a bit of humor, a bit of wisdom, a bit realism, a bit of fantasy; it's a little tragic, but also quite light... and it does it damn well.