The Wikipedia article for Virginia Oldoïni, Countess of Castiglione, places her behind the scenes at some critical points in Franco-Italian history, France supporting Italian unification and Prussia not occupying Paris. She was part of the demi-monde, women on the edge of society supported by wealthy lovers. The Second Empire supported a verdant demi-monde, including the Countess of Castiglione, La Paiva, and Cora Pearl. Britain wasn't far behond - beautiful women who blended into the aristocracy were known as "professional beauties" who were eagerly sought out by hostesses preparing guest lists. Professional beauties are discussed here. The most famous professional beauty was Lillie Langtry, the inspiration of Judge Roy Bean, who styled himself "The Law West of the Pecos."
The Countess was aware of photography and actively participated in developing it as an art and science. She was cousin to the Conte di Cavour who oversaw the unification of Italy under the Savoia family, possibly with some pillow talk assistance by the Countess when she was with Napoleon III. She spoke to Bismarck in secret, keeping the Prussians out of Paris (but not out of making the error of declaring Wilhelm I Kaiser at Versailles, ensuring a grudge match in 1914 and another in 1939).