Oliver Masucci went out as Adolf Hitler in public as part of the film's guerilla-style scenes. All reactions from the civilians were real, and Masucci improvised his dialogue.
The beginning scene where the camera shows clouds in top down perspective and slowly fades into modern day Berlin is a direct homage to the 1934 Nazi propaganda movie Triumph of the Will (1935) by Leni Riefenstahl.
The character Ulf Birne, the head of Germany's right national democratic party, "NPD," is a parody of Holger Apfel, who was the head of that party from 2011-2013. ("Apfel" means apple, while "Birne" means pear.) In the original novel, set in 2011, Adolf Hitler actually met Apfel, who introduced himself as the chairman of the NPD and a huge fan of Hitler's show. In 2014, Udo Pastörs was chairman of the NPD.
A poster for Back to the Future (1985) can be seen on the wall In Fabian's room when he is first reviewing the footage of the boys playing soccer. This echoes how Hitler has arrived in what is, from his perspective, the future. Sawatzki's clothing is also similar to the one of Marty McFly in the "Back to the Future" movies.
When Sensenbrink encounters the unknown actor portraying him, he suggests that Bruno Ganz could have played the part instead. Ganz was famous for playing Adolf Hitler in Downfall (2004).