Hugo and Georges are connected from the beginning of the novel, but they seem very different on the surface. One is a helpless street urchin who likes to play and make trouble. The other is an accomplished business person, and secretly, an acclaimed filmmaker rumored to have died. Notice also that Georges is already serving as godfather to Isabelle, so when Isabelle and Hugo become friends, the question on the table is whether Georges will step up and save the orphan from his life of suffering.
In the end, we see a picture of bliss: Hugo and Georges watch movies together every day, and Hugo gets to have a family where he isn't abused by a drunk (his custodian was formerly an abusive uncle). Georges gets to have his identity back, living in a peaceful way with people who actually know who he is and appreciate his work. Together, they figure out a more peaceful way of life, which was unavailable to them before.
This path was unavailable to Hugo because of his antagonistic relationship to adults (not that he can be blamed). It was unavailable to Georges because Georges was unable to deal with the truth about his life. That means that although they seem incredibly different, Georges and Hugo are essentially the same. The Invention of Hugo Cabret is technically Georges' invention, another good reason to view the characters jointly. This joint perspective shows that Hugo's progress comes from finding authority, and Georges's progress comes from finding fun, mischief, and play.
