Les enjeux de la mort

Evan C. Kim did all of his own stunts, including the martial-arts fighting.

Director Peter Swan tells Inspector Callahan that he encountered Harlan Rook at every film screening or other public appearance, where Rook's comments showed that he knew everything about Swan's films. Rook also constantly pitched his screenplay to him. Despite this extensive contact and familiarity, Swan does not recognize Rook when he works closely with him on a daily basis as his special effects supervisor under a fake name.

That's the whole point, Swan is dismissive of Rook and doesn't consider him worthy of his time. It's not out of character for the arrogant Swan to not recognize the face of some special effects technician.

Harry Callahan's character name becomes Harry ''Callaghan'' in the Italian version and titles because the local distributor thought it sounded better.

Edited into The Green Fog (2017)