Emile Zola 
Paris The Three Cities Trilogy 

"Paris" is the third of Emile Zola’s "Cities" trilogy, following Lourdes and Rome. Abbe Pierre Froment has now been disillusioned in his faith twice, once at Lourdes and again in Rome. On his return to Paris he decides that, if he himself no longer believes, he can at least still give hope to others. He joins Abbe Rose in attempting to succour and assist the poor of Paris. (Goodreads)