Best mystery TV mistakes of 2009
Continuity mistake: At the end of the episode, the Mercedes S class that is burning is not the same car that Castle drove previously in the episode, it's an older model one. Either it's a mistake or has to do something with the plot resolution, decide yourselves...
Factual error: In the banner for the exibition in France at the start, the French isn't right. It says "Opéra nationale" and "La morte de Marie Antoinette Des objets fabriqués de le temps de Marie Antoinette". It should be "Opera national" and "La mort de Marie Antoinette Des objets fabriqués à l'époque de Marie Antoinette" or "des objets fabriqués du temps de Marie Antoinette".
Factual error: At the beginning of the episode, Patrick Swayze is looking at photos of two Iraq veterans who have been murdered. He identifies one as a Marine Lance Corporal and the other as an Army PFC, but both pictures show men in U.S. Army uniforms. A bit later, his partner, who is supposed to be a Marine vet, refers to his decision not to "re-up," using the Army term for re-enlistment, rather than "ship over," as it's referred to in the Navy and Marines.