After after spotting the French Ambassador's automobile outside of the French Embassy in the Netherlands, the Japanese terrorists each chamber their weapons. The Japanese terrorist who is later injured is seen loading a VZ 61 Skorpion which has an olive gun sling attached to the pistol's grip. Later, inside the French Embassy, the same VZ 61 Skorpion is seen without the olive sling attached.
Though the OPEC raid took place in December, there is no snow on the ground in Vienna, and there are green leaves on the trees when the raiders disembark from the tram.
During the 1974 French Embassy attack in The Hague, someone states to one of the hostage takers, that French President Georges Pompidou died "back in February" Georges Pompidou actually did in April of 1974.
At the end of Part 1, Carlos and his men are waiting at a tram station in Vienna. Behind them is a red sign that says "Kebab and Schnitzel". Kebab was not introduced in Austria until the mid nineties.
As the terrorists are waiting for the tram before the 1975 OPEC raid, a sign for a kebab stand is visible. Vienna's first kebab stand opened in 1983.
(at around 23 mins) "French embassy The Hague, Netherlands" scenes are clearly shot in Portugal, seen by license plates of parked cars on the street are old Portugal style/typography, not old Dutch (typography), while half a minute before we see an actual shot in The Hague, one of the terrorists arriving by taxi (which is too new).