A simple exercise: read through the real Chevalier d’Eon’Eon wikipedia page, and try to guess if he was a man or a woman.
Now, there is an anime based on this historic character and it’s history which resolves around the King Louis XV, Le Secret du Roi and Robespierre. Although they had introduced magic into the story, the result was quite interesting and made me like very much the show, specially the thought of the duality between the solitude of kings versus how evil/machiavelli/good they are.
Of course it also features some ideas of le Révolution Francaise opposing the existing honor to the King, which lead to a lot of intrigue and betrayals.