I love this scene: Montparnasse tries to rob Jean Valjean, but gets trounced and lectured to instead. And Gavroche picks the would-be-mugger’s pocket, leaving the coins for Mabeuf, whose hedge he’s hiding in.
It’s got quick reversals, irony, and over-the-top coincidence.
“Who was this old gent? The reader has probably guessed.” But Gavroche doesn’t know him, and he’s the viewpoint character for the scene, so the narrator dances around his name instead of giving it.
Incidentally, Gavroche is trying to steal apples – which is what Champmathieu was arrested for. Back in that chapter it was mentioned that it could be excused of a boy, but not a grown man.
These last few chapters bring back two looks at Valjean’s years as a prisoner: The chain gang being taken to prison, and his scare-em-straight tale to Montparnasse. The story has moved on, structurally…but of course Valjean isn’t allowed to move on. That’s the whole point of his arc, that society won’t let him just be, and always sees him as an ex-convict.