Napoleon III, Empress Eugenie and her Secret Duke of Sesto: Imperial Wedding of Old Paris

 
From the publishers:
This book tells the tale of the elusive quest that preceded the most lavish wedding of 19th century Paris, the Imperial Wedding at the Cathedral of Nôtre-Dame, in which a Spanish Countess, rejected by the Duke of Sesto, was elevated by Napoleon's nephew to be Empress of the French, the most stylish and bejeweled woman in all Europe.