In order to bypass Herzel censorship, it would have been likely published when Verne became an acknowledged author, allowing this novel passing thanks to his fame.
It would have been a mixed reaction. Public was used to the optimistic tone of Jules Verne's novels (while they were modified due to editor's asks, many endings were more pessimisstic than published versions).
But not totally misunderstood : Jules Verne best works are made of drama. Just look at Nemo, this solitary, misantrhop and rude character. You admire him but you don't like him.
Or the end of Mysterious Island where everything they created simply disappear, even if the end was "remade" it's still depressing.
So, Paris in the XX would have been quite shoking (especially if it keeps the poo jokes) but appreciated by many. It would have maybe put to Verne a prodhonist reputation (true or false), especially if other nobles like "The day of an american journalist in 2889" pretty dark, or "The eternal Adam" that is basically a post-apocalyptic novel are published as well.
Verne would have became more of a social sci-fi writer than pure technical one. Somewhere between Kafka and Orwell mixed with more classical novels.
Again, it wouldn't be that of a big issue, Hertzel was quite frightened of Nappie's moral policy (victorian moral with mustaches) with some reason : Verne could have issue with a too much pessimistic (and relativly reactionary) view on technology and his refuse of positivism.
But with his fame and political positionnement (social conservatism), it wouldn't led to too much trouble. Maybe less sells, but more fame.