Near the end of the movie (after about 20 min), a rich man gives Karl-Bertil a band with national flags. In the next scene, the band is attached to a driving car. Blowing in the wind, one of the flags is a German Nazi flag with swastika.
Shown on TV in Sweden every Christmas Eve since 1975. It is also shown on TV every year in Norway.
The story probably takes place in the 1940s but there are numerous, likely purposely, historical errors. For example the first Swedish TV broadcast didn't occur until 1954, and the movie they watch is referred to as "old" even though it's from 1944.
Based on a short story by Tage Danielsson, which was published in his book "Sagor för barn över 18 år" in 1964.