On the commentary for the Blue-Underground DVD release, Director/Blue-Underground president William Lustig told director Enzo G. Castellari that "Il Cittadino si rubella" was the inspiration for his film Vigilante (1982). They both started laughing because "Il Cittadino si rubella" was retitled "Vigilante II" when released on video in the United Kingdom. This means the film that inspired the other illogically became its "sequel."
All of the interiors in the film were shot before the exteriors, so the wounds on Franco Nero's face were invented before the actual beating had been shot. They later had to coordinate the beating to match the makeup he had had on while shooting the interiors.
Franco Nero did his own English dubbing in the English version as Nero knows English very well. Nero know both Italian and English very well.
During the scene at the dry dock, the Achille Lauro can be seen in the background. The Achille Lauro was hijacked by the Palestine Liberation Front in 1985.