Someone else in these comments said s/he wonders what lives the people ended up living who were seen in old photos/videos. Your comment makes me wonder what life this boy (well, he's our senior) lived, and what his impact is beyond being a participant of a curious event in a YouTube video. I guess he had a paper trail, relatives, etc, but there's probably no way to identify him from the present (except if someone's grand-grandkid can give us an anecdote about his grand-grandfather seeing a kid being shoved at the moving walkways in Paris..

There's a good chance he was fighting in WWI being in his mid 20s.

If he survived that he lived through economic crisis in the twenties and thirties and ultimately WWII including occupation and terror in France.

And ultimately if he got old enough he could have witnessed the early cold war but also European economic bounce back and begining reconciliation between former enemies.