If your ancestor was in France as either a native or a foreigner during the First Empire (1804-1814) and did anything at all by way of travel, trade, crime or suicide, there is a good chance he or she was written up by the spies of the time. The French Empire of that time included Spain, Italy, Switzerland, Belgium, The Netherlands, and various German and Polish Duchies. Napoleon ruled it all and wanted to know all that was happening all the time in all of his empire.
The two Ministers of Police -- firstly Joseph Fouché, the Duke of Otranto and a wily dog; secondly General Savary, the Duke of Rovigo (the dashing fellow above) -- therefore sent him daily reports on all happenings of import (and not much) in the empire. The network of spies was enormous, and they reported back to police headquarters with whatever they thought might be of interest or use. They come across as obsessive and silly at times, but they have left a marvelous record: who received a passport, who left France, who was arrested, what little crimes were committed, political gossip, the evacuation of a church, the death of an English agent, the theft of a gun.
The bulletins are in the National Archives in hundreds of cartons. They are also all available online in two series of books entitled "La Police Secrète du Premier Empire". The first set, edited by Ernest d'Hauterive, is of five volumes, covers the Fouché years of 1804 to 1810. The second set, edited by the National Archives' expert on the First Empire, Nicole Gotteri, is of seven volumes and covers the Savary years from the second half of 1810 to March, 1814. Both sets have good indices, including names, but one must check each volume's index separately.
Most of the first set is online, in various locations, with the Internet Archive having all five volumes. Most of the second set is on Google Books, with a snippet view, which is often enough. Many libraries have both sets. A good resource and a fun read.
©2011 Anne Morddel