Karel Cernik mentions the train that broke through the Czech border into West Germany. That happened on September 11, 1951.
In his autobiography, director Elia Kazan stated that the crew and cast were subjected to harassment from the East German government, which threatened to harm family members still living there. The first director of photography resigned due to these threats. Kazan also praised the crew and circus performers' dedication to the project despite the harsh conditions under which they lived, and revealed that he developed a close friendship with Hansi and several of the other performers.
As noted by contemporary sources, Salto mortale (1953) is loosely based on real incidents involving the Brumbach Circus, which escaped from Communist-controlled East Germany to West Germany in 1950. Unlike the escape in the film, however, circus owner Gustav Brumbach slowly moved a few camouflaged pieces of equipment and performers at a time, over a period of several months.
Salto mortale (1953) was based on the novel Man on the Tightrope by Neil Paterson (New York, 1952). In 1952, Paterson first published his novel "Man on a Tightrope: The Short Novel" as a novelette in the British magazine Lilliput under the title "International Incident."
Hildegard Knef was supposed to play the female lead, but shortly before filming began, Elia Kazan cast Gloria Grahame instead.