The production unexpectedly ran out of money halfway through and halted for several months in order to find new investors. This ended up working in its favor, since Marcell Nagy was going through puberty, and by the time they restarted, he looked physically more mature, taller, and his voice deeper. By the time his character enters and survives the death camp, he looks several years older than when the film began, adding an element of reality that otherwise would have been created with make-up.
The Nobel Prize winning writer of the book "Fateless" viewed the true-to-fact set of the death camp Buchenwald, and he was shocked of the sight. He left the set in a short time.
With its estimated budget of HUF 2,500,000,000 (twelve million dollars), this is the most expensive Hungarian production to date.
Forget-Me Not Street is a real street in Budapest about two blocks from the East Station (Keleti Pályaudvar).