An act of the king of Prussia on January 6, 1845 made her Duchess of Sagan. Napoleon III did the same in France, for her son Louis. The double title, both Prussian and French, meant that the duc de Sagan was a neutral party in the Second World War. His house (the Château de Valençay) was a safe place to keep pictures and other things from the Louvre when German soldiers were in France. 