The Prussian Terror by Alexandre Dumas

Historical novel set in 1866, during the Austro-Prussian War. According to Wikipedia: Alexandre Dumas, born Dumas Davy de la Pailleterie (24 July 1802 – 5 December 1870) was a French writer, best known for his historical novels of high adventure which have made him one of the most widely read French authors in the world. Many of his novels, including The Count of Monte Cristo, The Three Musketeers, Twenty Years After, and The Vicomte de Bragelonne were originally serialized. He also wrote plays and magazine articles and was a prolific correspondent.