Stefan Lux was a Jewish Czech journalist, who committed suicide in the general assembly room of the League of Nations during its session on July 3, 1936, to alert the world on the perils of German anti-Semitism. After shouting "C'est le dernier coup" ("This is the final blow") he shot himself with a revolver.
The film is based on the very successful and controversial play "Der Stellvertreter. Ein christliches Trauerspiel" ["The Deputy, a Christian tragedy"] by German playwright Rolf Hochhuth, which started a lot of heated discussions, arguments and even diplomatic tensions after its premiere at West-Berlin's "Freie Volksbühne" on February 20, 1963. Within the same year, the play was produced at additional theatres in West-Germany, Sweden, Switzerland, Denmark, Finland, France and Great Britain. "The Deputy" has been translated into more than 20 languages and the play has been produced in more than 80 cities worldwide since. It is now regarded as a classic of German post-war theatre.
The Vatican did not give permission to shoot the film in its buildings. After searching for a location of adequate size for the scenes taking place in the Vatican, Costa-Gavras finally chose Europe's largest building, the Palace of the Parliament (Palatul Parlamentului) in Bucharest, Romania. Some of the outdoor scenes were shot in Mogosoaia Palace, approximately 14 kilometers northwest of Bucharest.
When Gerstein witnesses truckloads of corpses being dumped into a mass grave and his driver remarks, "The crematoriums are overworked," this is in no way an exaggeration. There were actually efforts underway to solve this 'problem.' E.g. the 1942 patent-application T 58240 KI. states, "There exists the necessity to remove the constantly accumulating large number of corpses quickly, safely and hygienically." It proposes about 18 m high *continuously working* furnaces, in which "the corpses to be incinerated while fed into the furnace are constantly exposed to the flames and the gases from combustion which rise in opposite direction of their movement. Multi-part fire-clay sliding doors allow ... jamming of objects to be burned to be alleviated from outside ... Most ashes collect ... in the ash-collection-container, where they are constantly subject to the flue gas, so that possible not completely burnt residues can still post-burn and burn out in this ash-compartment." The capacity of one single unit of these incinerators was estimated at 1200 to 4800 corpses per day, or (conservatively assuming 300 days of operation per year) to 360,000 to 1.4 million per year.