Factual error: In the opening sequence, the convicts are located in a dry dock pulling on ropes supposedly connected to a listing ship in the distance. The convicts are standing in 2 to 3 feet of water which would indicate that the dock is "dry" and that the dock gates are closed. The ship will be unable to enter the dock under those circumstances. If the gates were open enough to allow the ship entry there would be 20 to 30 feet of water in the dock and the convicts would need to be up on the top of the dock to achieve their objective.
Factual error: In the scene at the inn when the man's artificial leg is pulled off, the leg's socket is a modern ischial weight bearing socket, which wasn't invented until the 1950s.
Continuity mistake: Toward the end, Thénardier is being dragged down the stairs after Marius took back the gold ring Thénardier stole off his unconscious body previously. The gold ring appears and disappears several times as Thénardier is being pulled out of the room, down the stairs, and out the door. At the end, Marius shows the gold ring to Jean Valjean as he is dying, which was last seen on Thénardier's finger as he was being pulled out the door.
Continuity mistake: In the scene early in the film, where Valjean is singing in the church (after the police brought him back to the minister for stealing the silver), he has a wound on the right hand side of his head (from being hit by the policeman's stick/truncheon). Depending on the camera angle, the size of the wound and its appearance alters- sometimes it is quite small and flat, other times raised. Also sometimes there is a trickle of blood from it and other times not.
Continuity mistake: In the scene where Valjean is captured and brought back with the silver, the officials that apprehend him take off their hats. However, a few shots later, when the Monsignor collects the silver back, the official who addressed him has his hat on.
Continuity mistake: When Éponine (Samantha Barks) sings "On My Own", towards the end of the song, her hands come into shot, they are immaculate and manicured. Immediately after the song, she goes into a building to retrieve Cosette's letter to Marius, whilst holding the letter her hands are filthy with dirt under the nails.
Visible crew/equipment: When Éponine sings "On my own" towards the end, when she whispers "I love him" you can see the shadow of the cameraman on her left cheek as he leans closer, and then disappear as the camera apparently zooms out and the cameraman backs away.
Factual error: When Javert is singing "stars" he is walking a rooftop that appears to be another church across from Notre Dame. The church of Sainte Chapelle is in that direction, but looks nothing like what is depicted in the movie. Later when Javert has his solo on the bridge behind Notre Dame, the building he was standing on earlier should be visible from that angle, but was not included in the background.
Continuity mistake: At the very end of the movie during the final song - the large red flag shows different amounts of wind from many directions to no wind. Worst of all during the final 15 seconds of the movie the big red flag final shot is played in reverse so the flag waves itself along with all the little flags. (02:29:26)