In this chapter we see Javert come to the Mayor’s office and demand that the Mayor remove him from his position. It’s a shocking turn. Everything about Javert’s demeanor and additude is changed. He is sullen and reserved, deferring to Mayor Madeleine and clearly sorry for what he has done. What has caused this change of heart? Apparently Javert had reported his belief that Madeleine was in fact Valjean to the police chief in Paris - and had heard back that this accusation was impossible, as they had the real Jean Valjean in custody.
Javert’s internal logic is sound, but harsh, and it matches his warped sense of justice. In his calculus, he still believed someone on the outside of society should never come against someone on the inside, and all hierarchies must be respected. With his accusation overturned, he is now guilty of the thing he has fought against repeatedly, and believes he must be held to account. Time will tell what actually transpires, but Madeleine says he won’t be removing Javert.
So what’s the story with this other Jean Valjean? How is this possible? Who is this prisoner? It looks like the next set of chapters will be focused on resolving that question.