Feels quite a few years ahead of its time. I know this new wave style was very popular in the 60s, but this was surprisingly early in the decade for a film of this kind of style. I forgot it was '61 while watching it, and assumed it was more like '64-'67 based on how it felt.
I know that may not sound like a massive difference, but it did at least make me go from saying "this seems heavily inspired by Godard's Pierrot Le Fou" to saying "wait, was Pierrot Le Fou inspired by this?"
Plot is kinda all over the place, and a little hard to follow at a point, but it's not super important. The style and the humour and just the overall feel is more essential here, and a good deal of it works.
It's not in any way pretentious, which is a word you could arguably throw at some new wave films of this era, and it doesn't feel unpolished, either, striking a good balance between slick and chaotic.