The magic toy
The central symbol in the novel is the Invention itself, which Hugo did not make; Georges did. To say it's Hugo's invention is to remind the reader that Hugo and Georges are in this story together. This is not a book about one character or another, but the story of how unlikely characters become a family. Therefore the magic toy represents family and home. This makes sense because it's what Hugo wants most. When his friend helps him unlock it, that's a symbolic way of saying that friendship helps him to feel restored. When he sees his father's favorite movie, he realizes that the toy is magical, and finally, the toy shows him a name: Georges Méliès. This will be Hugo's new family. The magic toy worked.
The toy shop owner/magician/filmmaker
To say that Georges is a regular character would be a little silly. He makes magical toys and magical films. He is quite literally like a wizard. By the end of the novel, he is literally dressed like a magician, making Hugo's story into something like The Sorcerer's Apprentice. But Georges's magic is mostly the peace and joy he gives to Hugo, and the movies they watch together. To Hugo, Georges is a magical superhero, and the reader gets the impression that Georges really needed to be reminded of that.
The allegory of the street urchin
The boy's story is so allegorical, it might even be archetypal. Orphaned by the sad loss of his parents, left under the custody of an unhealthy person, Hugo must make decisions for himself from a young age. His commitment to life comes in the form of his penchant for mischief and play, but after all, he just wants adult attention. The novel is about the boy's journey from family, to absolute loneliness, back to family again.
The girls as catalysts
The girl characters in the novel help to establish the relationship between Hugo and Georges. First, Isabelle guides them toward one another by befriending the urchin and hanging out with him. Then Etienne joins the mischief by adding her teacher to the mix, a persistent fan of Georges's films. Eventually, both of these catalystic moments help to push Georges toward accepting Hugo into his custody.
The three false dads
When he hears his uncle has turned up dead, the boy flinches, dropping milk he was obviously trying to steal. This forces him into a chase through the station, followed by a very angry Inspector, but Georges saves him. This is more symbolic than literal. It symbolizes the role that authority plays in Hugo's life. The uncle represents authority that overstayed its welcome. His authority is worst of all, because he couldn't even find enough stability to save himself, let alone Hugo. Then is the Inspector whose authority comes from his role at the station. But he doesn't see Hugo as a real person, but rather as a function of his job. Finally, there is Georges, who comes dressed as a magician, signaling his readiness for Hugo's crazy boyishness. Georges is the only adult who is finally willing to play with him. Therefore, he is Hugo's new father.
