Continuity mistake: When Sophie gets out of the back of the armored truck, she is not carrying anything and, again, as she is running along the side of the armored truck to get into the passenger's side, we see both hands and she isn't carrying anything. A couple of scenes later, as she and Robert walk up the steps to Chateau Villet, she is carrying her gray overcoat and handbag. They can be seen even better when Teabing is kissing her hand in welcome.
Plot hole: Fache says he believes Langdon killed all those people because Aringarosa told him Langdon came to him in confession over the murders. We know Langdon made no such confession, so what made Aringarosa involve Langdon in the murders in the first place? Aringarosa never saw the curator's daily planner, his email, and wasn't there to see the message on the floor, so other than Langdon conveniently being in town for his book signing, why did Aringarosa name Langdon? If he was just telling that to Fache so he would have someone to arrest, Aringarosa could have named anyone.
Character mistake: Langdon points out that the Templars were slaughtered on October 13th, 1307, and Sophie comments, "Friday the 13th", implying that this is when the fear of Friday the 13th originated. In reality, fear of Friday the 13th didn't really begin until early in the 20th century.