Jules Verne 
The Flight To France 

Natalis Delpierre, a Captain in the French Army, is going to see his sister Irma, who lives in Prussia in the service of Madame Keller and her son Jean. When the war between France and Germany breaks out in 1792, Natalis, Irma and several others need to flee to their home country while Jean joins the Prussian Army. But when he battles his superior officer because of a woman, he also needs to flee fast …