The movie was banned in Spain, which was still ruled by Generalisimo Francisco Franco, the fascist victor of the Spanish Civil War.
As they were not allowed by the Spanish government to film in Spain, Fred Zinnemann and Alexandre Trauner stayed for two days at the Frontón Hotel in Vitoria (now Vitoria-Gasteiz) and went around the city to get pictures and information about buildings and people trying to reach the "intimate heartbeat of the city" in order to later recreate them properly. No local newspaper took the news maybe due to censorship.
The film begins with a pre-credits sequence set in 1939, briefly displaying Miguel Artiguez's escape over the border into France. The first scene after the credits begins with a superimposed caption reading "Twenty Years Later." The first showing of the film on British television deleted the pre-credits sequence entirely, but retained the post-credits caption, leading to millions of new viewers of the film to ask, twenty years later than.... what, exactly? The missing pre-credits scene was eventually restored when the film was shown on Channel Four in the 1990s, but, 30 years later still, it tends to be pot luck whether or not viewers get to see it.
Because of scenes showing Viñolas with a mistress and taking bribes, the Spanish government not only disallowed filming within Spain, but prohibited Columbia Pictures from distributing any of its films in Spain. Because of the Spanish boycott of Columbia's films, national television broadcast in the U.S.was delayed by about a month.