Truffaut's The 400 Blows begins with a series of shots all focusing on the Eiffel Tower. After all the times I've seen this film I can't figure out his motivation for starting the film this way. The tower is never referenced again during the film and the bulk of the story takes place in Montmartre, a low rent area of the city where the tourists go to "slum it" with working class and bohemian types. I guess this could just be another example of the high/low culture juxtaposition that new wave directors favored, or perhaps a commentary on Antoine's character who is metaphorically going around in circles?
Jean-Pierre Léaud's performance is one of my favorites in all of French new wave cinema. Truffaut's choice of hiring an unexperienced actor to play this role was a minor stroke of genius. I think with an experienced actor you would've seen a performance that wasn't as naturalistic, since it would've been an actor trying to act like a troublemaking young teenager. Truffaut just cut out the middle man and hired a real troublemaking teen. This way he got someone who could actually fait les quatre-cents coups (raise hell) instead of having to be directed to do so.
Truffaut's cinephilic tendencies are clearly shown when Antoine and his friend cut class to go to the theater, but there is perhaps a reference to the earlier history of film. During the scene when Antoine is on the ride that spins around in circles, there are some shots from his POV. The bottom half of the screen shows the opposite wall of the ride, but the top half shows the people watching the ride spinning. This creates an image suggesting a zoetrope or a kinetoscope, those pre-filmic visual toys that showed moving pictures.