This week in the War, 18–24 August 1941: Pierre Georges fires the first shot in Nazi-occupied Paris
German notice proclaiming that, as the result of the killing of a member of the German armed forces on 21 August , Frenchmen under arrest would be considered as hostages and could be shot as a reprisal for future killings of German personal. [Public domain, wiki]
On 21 August 1941, a German naval adjutant named Alfons Moser was shot and killed at the Barbès-Rochechouart métro station in Paris. The act marked the beginning of an armed struggle against the Nazi occupation.
The shot was fired by a communist named Pierre Georges, also known in the Resistance as Fredo, and later as Colonel Fabien. He was an experienced fighter, having served with the International Brigades during the Spanish civil war.
Command post of Pierre Georges (Colonel Fabien) during the 1944 Paris uprising, 34 rue Gandon, XIIIe arrondissement [Creative Commons Share Alike 3.0 unported]
The cycle of killings and reprisals continued in Paris and in other French cities in the occupied zone. (Six Frenchmen were shot by firing squad as a result of the Barbès-Rochechouart killing).
Georges was captured, tortured but escaped to play a role in the uprising that helped liberate Paris in 1944. He died later in the war as a result of a landmine.