Continuity mistake: During the chase scene, there is a Citroen XM series II (the citroen sign in the middle, on the front) and then there's a Citroen XM series I (the citroen sign on the driver's side, on the front). It changes back and forth a couple of times. There's also a difference at the bottom of the car; the series I carries the name Citroen XM on the left side, while the series II bears a Citroen sign on the left side and the XM sign on the right.
Continuity mistake: During the big car chase the Audi S8 rams the Citroen, pushing back the headlights on the Audi but on the subsequent scenes in the town the front of the Audi is intact.
Continuity mistake: When Gregor tries to sell the case, he puts the Jeep into park (we hear the sounds of an automatic transmission, and in a brief shot of the pedals there's no clutch). But he jolts the car forward a minute later without shifting into drive.
Continuity mistake: At the end of the Paris car chase with the BMW M5 and the Peugeot, Jonathan Pryce fires a few shots at De Niro and Jean Reno in the pursuit car. One shot takes the left wing mirror clean off, and De Niro even jerks his head to the side in reaction to the shot. The mirror comes off in mid frame, and you can even see the adjustment wires dangling from the mirror base. In all subsequent scenes, the mirror is back on the car.
Continuity mistake: In the early scene of the arms deal, when they are waiting in the car for the arms dealers to turn up, Robert De Niro (in the back seat) is initially unshaven, but then later in the scene he is clean-shaven.
Continuity mistake: In the car chase after the bald guy with the suitcase, when his car approaches a fish market inside Nice, you can see a guy with a water hose running to the right, to avoid being hit by a car. His hose is connected to some point on the left, however in the following shot there is no pipe across the road.
Continuity mistake: When Spence draws the sniper ambush scenario on the whiteboard and gets stopped, the cup of coffee is set down on a small table. When Spence backs away into the cup, its handle has turned itself around. (00:27:30 - 00:28:20)
Continuity mistake: After the first big chase scene, Robert De Niro is seen with the group in their hideout. As he treats the man who was injured, he puts the bottle of alcohol down twice.
Continuity mistake: In the apartment with Diedre, Seamus's hand jumps from the bottle of scotch to his side.
Continuity mistake: When Gregor is in the chase scene at the old stadium, he runs/falls down some stone steps and loses his wire-rimmed glasses. In the next scene, he is wearing them once again, looking over his shoulder for Sam, who is chasing him.
Continuity mistake: At the beginning, De Niro wakes up and is offered a cigarette from Jean Reno. The cigarette changes hands as the shot changes. (00:09:40)
Continuity mistake: In the middle of the film when Gregor is selling the suitcase onto the Russian guy in his jeep, you can see that when Gregor puts his foot on the accelerator the other guy jerks about and the last shot we see his head is down, yet the following shot he is looking at Gregor before the splatter of blood on the window. (00:55:05)
Continuity mistake: Near the beginning, when the group are talking over the ambush to steal the case, Sam walks to the table where Deidre is and Gregor follows. When Sam accidentally knocks the cup off the table, Gregor's hand changes position on the cup between when he catches it and the following shot. (00:14:30)
Continuity mistake: On the freeway chase scene between the BMW and the Peugeot, when the BMW gets flipped over and slides and the Peugeot hits it, the BMW goes over the edge and Peugeot slides round almost facing backwards. In the following shot from the ground the Peugeot has changed direction. (01:29:55)
Continuity mistake: While chasing Deidre the dividers between the lanes change. Right after the chase leaves the tunnel all the views of the road scene looking back at the cars show a road with a solid concrete divider separating oncoming traffic. But all the "driver's eye" views of the road show a post and guard-rail type divider.
Continuity mistake: At the start of the Nice ambush for the silver case, the bad guys are shooting at Sam who is leaning against a grey car. He ducks behind it, but in the following wider shot Sam is still leaning against the grey car. (00:43:10)
Continuity mistake: At the start of the first chase scene in Nice, Jean Reno walks across the road to test the traffic lights device. There are concrete cones to the right of the screen, NOT by the grocery store, yet, on the overhead shot, when he is trying out the lights, three have appeared in front of him next to the grocery store. (00:41:55)
Continuity mistake: During the arms deal scene at the beginning, when Vincent and Spence go underneath the tunnel approaching the arms dealers boss, one of them shouts, "Stop!" He raises his right arm when shouting, but in the following close-up he has actually raised his left arm. Zoom in required. (00:21:45)
Continuity mistake: Just before the group goes out to collect the weapons from the buyers at the beginning of the film, the group are gearing up to go out, and Sam is talking to Deidre about the arms people. When Deidre burns the piece of paper and walks away her hair is obviously going down her back, but in the following shot there is now no hair on her back. (00:15:50)
Continuity mistake: In a close up of one of the alloy wheels on the BMW during the big chase, the wheel has changed style to a cross spoke.
Answer: It's a while since I've seen the movie but if I'm remembering correctly, the meet was at short notice. Gregor had the case prepped for the swap but didn't have a chance to paint it in enough time for the paint to dry properly.
The_Iceman