Factual error: The 20 banknote shown is multicoloured, but the real one is plain blue. (00:40:40)
Factual error: When Ewan McGregor drives to Belmont MA to visit Paul Emmett, he checks the mailbox to see whose mail it's addressed to. It shows the name Paul Emmett, address, Belmont MA 02324, which is the wrong zip code; it is the zipcode for Bridgewater MA, and Belmont MA should be 02478.
Factual error: In the flashback, when Teddy was among the soldiers liberating Dachau, there is a semi-circular sign above the gate that says "Arbeit Macht Frei". Dachau had a sign with those words on it, but its sign was oblong. The sign at Auschwitz was that shape.
Factual error: Bobby extracts two teeth to get the combination to the next room. When he looks at the teeth, the numbers are on the tooth root. To do this would be impossible without removing the teeth first. (01:02:05)
Factual error: Detective Bowden's son is ejected from the front of the car and there is a hole in the front windshield. The collision was a straight side-swipe and his momentum should have taken him out the passenger-side window. He would have gone out the windshield if the car had been rear-ended or if they had crashed head-on into something, but the car came to rest in an open field.
Factual error: During the breakfast scene with the bacon a box of Cheerios is seen on the counter with the red check mark on it. This indicates that the cereal is American Heart Association approved. The check mark campaign didn't begin until 2009 even though the movie supposedly takes place 3 years prior, in 2006.
Factual error: When Cobb arrives at Los Angeles International Airport and is going through immigration, the officer stamps his passport with a black stamp. All passport stamps in the United States are universally the same with a blue oval and pink letters marking the date in the center. Plus the fact that US citizens don't get their passports stamped when they return to the country.
Factual error: When Luke puts the starting cables on the battery of the pick-up truck sparks fly from the connection. However since he hasn't connected the cables to anything on the other end yet no sparks should be visible. Next to that the battery is nearly dead so there is no power to give the sparks in the first place.
Factual error: When the Senator is looking at the rent ledger, there are entries for each property as well as the date that money was collected. One of the dates is 2/29/74, yet 1974 was not a leap year. The only leap years in that decade were 1972 and 1976. (00:56:30)