Emile Zola, "Lourdes" (1894 French version). One of the most popular French novelist's. 

  "Exhausted by the twenty volumes Rougeon-Macquart he just completed, he seeks new life literature. In returning a cure Cauteret he discovers Lourdes. It is the frame of the trilogy, Lourdes(1894) , Rome (1896) and Paris (1898), which tells the wavering faith of a priest, Pierre Froment. Zola has field inquiries and (...) séjounre 13 days in Lourdes (1892). Publication of the Paper was a huge success 121 000 copies sold in first two months. 

On the merits of Zola's Lourdes is the anti-Lasserre. A rationalist view, at least dubious to the supernatural, placed on the role of charitable pilgrimage. " From J F Labourie "Notoriété de lourdes" in "Lourdes, bernadette, une vie." ed Atlantica p.139