Plot hole: When the French conclude - incorrectly - that Charles Calthrop is the Jackal, they contact the British authorities and obtain his file photograph from the passport office. The photograph is of Edward Fox in character as the Jackal - but it shouldn't be! The Jackal and Calthrop have no connection. The Jackal never used his identity and did not apply for a false passport in his name. The photo should have been of Edward Hardwicke in character as Charles Calthrop, who appears in the closing minutes of the film. The two actors do not look anything like each other.
Plot hole: An important plot point (in the book and the film) is that Charles Calthrop - thought to be the Jackal, at that stage - played some mysterious part in the 1961 assassination of Rafael Trujillo, the dictator of The Dominican Republic, and rumours of his involvement came to the attention of MI6 and Special Branch, leading to the accidental exposure of the Jackal's false passport. In fact there is no mystery at all about the assassination of Trujillo and there were no shadowy foreigners involved. It was organised by Trujillo's own senior aides, amongst them General Juan Tomás Díaz, Antonio de la Maza, Amado Garcia Guerroro and General Antonio Imbert Barrera. The gunmen was later identified as Luis Aniama Tio. All the conspirators except Tio were arrested, tortured and shot. There was no panicked evacuation of foreigners who were involved with Trujillo's regime and no reason for them to be concerned - the government did not fall and Trujillo's brother Hector took over as President, ruling in a brutal and totalitarian manner for a further eight years. Any rumours of a mysterious Englishman would have been dismissed out of hand and would not have made it onto even the lowest level filing system anywhere in Whitehall.PEDAUNT
Continuity mistake: At the beginning, just after the title credit the President's car is machine gunned and you see the back windshield shatter and disintegrate. Moments later the car arrives at the airport with the windshield intact. We see de Gaulle get out of the car with the intact rear windscreen.
Factual error: When the Jackal is driving into France in his 1963-correct Alfa Romeo Giulietta, he passes a red Alfa Duetto. Those were not made until 1966. Likewise the Renault 12 or the electric locomotives.
Continuity mistake: When the Jackal is parking his car near the hotel, he parks in a small gap between two cars. When he gets out of his car, the leftmost car is gone.
Revealing mistake: When the Jackal is shot at the end of the film, he's thrown back against the wall of the room which moves, revealing it to be a wooden set. Additionally, the hole in the wall with the stunt cable can be seen in slow motion.
Continuity mistake: When the Jackal assembles the gun, to shoot the President, he puts the pieces on the table. Next shot the table is clear as he puts a chair on top to steady the gun.
Factual error: Charles de Gaulle's Citroen DS19, a vehicle that appears repeatedly, is an anachronism: it's a 1965 model used in a movie set in 1963. Although the design differences are few, they are noticeable from the outside. It's difficult to imagine why the production team used an incorrect car that got so much screen time (as opposed to the aforementioned 1966 Alfa and several other background vehicles).