Guillaume Schnaebel or Wilhelm Schnbele (1831 5 December 1900) was a French official from Alsace, best known for being arrested by Germans in the April 1887 Schnaebele incident (or Affair) which nearly led to war between France and Germany.Who caused the incident and why remains speculative, but it has been suggested that German Chancellor Otto von Bismarck was its instigator, for a number of possible reasons: inciting France into starting a war, gauging the extent of French support for Boulangism, or creating tensions with France to force the renewal of a Russian-German alliance of neutrality that was under debate at the Russian court.

Others see it as simply a series of unintended consequences, notable for the role played by France's General Georges Ernest Boulanger. This and a number of other incidents involving General Boulanger are elements of what is known as the Boulanger Affair, a series of embarrassments for the newly formed government of the French Third Republic that some consider to have nearly led to a coup d'tat.

The Prussian Secret Police (German: Preußische Geheimpolizei) was the Prussian

Secret Police agency of the German state of Prussia in the 19th and early 20th centuries.

In 1851 the Police Union of German States was set up by the police forces of Austria, Prussia, Bavaria, Saxony, Hanover, Baden, and Württemberg. It was specifically organised to suppress political dissent in the wake of the 1848 revolutions which spread across Germany. For the next fifteen years the Union held annual meetings to exchange information. Karl Ludwig Friedrich von Hinckeldey, the Police Commissioner of Berlin, was appointed by King Friedrich Wilhelm IV on 16 November 1848. He was to prove to be a key figure in the development of the secret police in Prussia as well as the whole union. By 1854, thanks to his close relationship with the king he was appointed Generalpolizeidirektor (General Director of Police). Effectively he was a minister of police independent from the minister of the interior. Von Hinckeldey founded the Berlin political police in Berlin and developed a Prussian information catalogue on political opponents, focusing on revolutionaries involved in the 1848 uprisings. But as he saw Paris and London as the centers of political intrigue he was keen to organize the policing of political opponents outside borders of national jurisdictions.

The Prussian Secret Police has historically held a bad reputation, as it was the model upon which the Gestapo was later founded. The Prussian Secret Police, however, did not routinely engage in persecution or the abuse of police powers, and did not behave in the way that other secret police forces might.

The Prussian Secret Police was renamed in 1933 as the Gestapo. Prussia itself was dissolved as an administrative entity following World War II.