The hero of the novel is the mysterious and distinguished Rodolphe, who is really the Grand Duke of Gerolstein (a fictional kingdom of Germany) but is disguised as a Parisian worker.
Isn't this always the case?
The book was an indictment of social conditions, but its real purpose was selling newspapers. It ran for 90 installments, and the final version was 1000 pages long.
Somehow that got boiled down into a comic book.