This is incredibly specific! Prisons wouldn't necessarily have different slang than what was common among the urban lower-classes. Also, slang would have been different in different parts of France, as linguistic differentiation was still very strong in the 19th century.

So here are some things to help you with 19th century Parisian "argot" or more specifically "l'argot des voleurs" - lower-class slang (as distinct from bourgeois or working-class slang):

Balzac's "Essai sur l'argot parisien" (1834).

Jacques Cellard "Anthologie de la littérature argotique des origines à nos jours" (Mazarine, 1985).

Ansiaume "L'argot en usage au bagne de Brest en 1822" (published in review "Le Français moderne" 1943-1944.

If you can find that last one, it sounds like it's exactly what you're looking for.

If you just want a general idea of how people talked in prisons in the 19th century, a book like Hugo's "Les Misérables" would be a great resource. I remember Zola's "L'Assommoir" having a good deal of working-class argot, and the edition by Chantal Pierre-Gnassounou has a helpful lexicon in the back.

If you're in Paris anytime soon, you should also maybe look at some of Coquebert de Montbret's archives in the AN, (cote 183AP) who did a lot to document regional slang especially among the lower-classes. I'm not aware of any articles or books published about Coquebert de Montbret's findings, but it might also be worth a look.