This is a good view of the different uniformes worn in Austria and Germany around 1900. It should be noticed the wearing of a German dress by Franz Ferdinand.
presumably the Kaisermanöver of 1908. General der Kavallerie Erzherog-Thronfolger Franz-Ferdinand v. Österreich-Este was the Chef of Ulanen-Regiment Prinz August von Württemberg (Posensches) Nr. 10.