Fournier, August, 1850-1920. Die Geheimpolizei auf dem Wiener Kongress : eine Auswahl aus ihren Papieren. 1913. XV, 510 S. : https://archive.org/details/diegeheimpolizei00fouruoft
https://babel.hathitrust.org/cgi/pt?id=uc2.ark:/13960/t7rn3kn56
Table of contents only: https://d-nb.info/579398021/04
As the actual papers were destroyed in a fire in the Haus, Hof und Staatsarchiv in 1931, this is pretty much all that is left. Well worth a rummage (well, I found something really interesting).