Plot hole: When Renee Russo was reviewing the tape showing the room with the painting to see who stole the painting, and the tape was blank because the heat generated from the suitcase hidden under the bench, why didn't she just back up the tape completely to see who put the suitcase there in the first place? (00:28:30)
Plot hole: At the end of the movie when everyone is standing in the gallery looking at the painting now back in place (with the smoke and sprinklers still dripping) they notice that now there is a new painting missing, the one Thomas stole for Catherine. However, none of the other metal wall coverings open or move except for that small side one revealing the empty frame on the wall. This makes no sense why only that one would suddenly open and none of the others. (01:40:50)
Plot hole: The "titanium-reinforced" briefcase Thomas leaves to block the descending security gate would have had his fingerprints all over it.
Plot hole: How did Catherine manage to show up at the original crime scene at the same time that the detective arrived? He came from across town; she came from Europe, as proved by her "jet-lagged" comment the next morning.
Plot hole: The beach could be reached only by vehicle, but they only had one car and they arrived separately.
Answer: On the commentary track for the DVD the director states that he has no idea how Thomas Crown stole the final painting.