Most surprising thing is this was his first film in 1959 and he was allowed to shoot in cinemascope. The anamorphic aspect ratio was new innovation at the time and reserved for huge Studio epic films - expensive to make. Just goes to show Truffaut was someone special.
In the italian version they added music already when he runs in the wood towards the beach before getting there, distorting a marvellous moment of breakout and self-liberation. I was glad to see the original version here. The sea is only a great question and I don't have any other comment to add
In my opinion, this film was inspired, for his creation, by Italian neorealism, in the way, for example, the children are made a symbol of the failure in human beings in the modern proletarian class. Aesthetically nice, not too much frenetic action and dialogues (like most of the later Nouvelle Vague films), it is perhaps more humane and honest than others french films.