In 1856 and 1857 she caused a scandal by becoming Napoleon III of France's mistress. This led to a divorce between her and her Italian husband, but La Castiglione herself entered the social circle of European royalty.
In the same year she begun her affair with Napoleon, she also started a collaboration with photographer Pierre-Louis Pierson, that would last for four decades. This resulted in 700 different photographs in which she recreated the signature moments of her life for the camera, usually dressed up in theatrical costumes. She spent so much of her fortune on this project she ended in debt. Some of the photos are very risqué for the time, with La Castiglione showing her naked legs and feet. In all these pictures her head is cropped out though.
As her mental health started to deteriorate, she spent her last years in an apartment in La Place Vendôme, that she only left at night. The rooms she decorated in funeral black with the blinds drawn. She also banished mirrors, probably so she wouldn't have to see herself grow old and losing her notorious beauty. At age sixty-two she died, and was buried at the Père Lachaise Cemetry.
Here are some of all those photos she spent her fortune to create:
And lastly - my favorite!
All pictures from Retronaut.