Continuity mistake: At the end when Meg steps out of the water, her pants are wet. However, when she enters the bedroom and finds the Phantom's mask, her pants are perfectly dry.
Revealing mistake: As the grating descends on Raoul, in two shots, large bubbles are flowing downwards. It's obvious, the film was reversed.
Visible crew/equipment: During The Music of the Night, you can see a camera shadow pass over the Phantom's and Christine's face. It's around the part where he says, 'Let your fantasies unwind'.
Audio problem: During the end of "Prima Donna" when everyone sings "Light up the stage." you can see some actors and actresses singing the word "light" but you don't actually hear it until a few seconds later.
Continuity mistake: When Christine approaches her family mausoleum, behind her you can see an above-ground tomb that has chains around the top cover. There is something on top of the cover that looks like a bouquet of flowers covered in snow, and there is not a lot of snow on the tomb. Later, when Raoul and the Phantom are fighting and the Phantom slashes Raoul's arm. Raoul falls backward onto this same tomb, and when we see him from above, rising, the chains on his side are missing, and there is suddenly lots more snow all over the tomb. The bouqet (or whatever it is) is missing. However, in the next shot that shows the same tomb, now there is much less snow, the bouquet is back, and one-half of the side chains have reappeared. You can see the continuity by the tree at the head of the tomb, and the triangular wreath laid at the head of the tomb.
Visible crew/equipment: When Raoul jumps down the hole into the mirror room, you see he is alone. Between when he jumps down, and the appearance of the phantom's reflection, if you slow down the movie you see a man in a gray shirt in the mirrors behind Raoul. He appears in at least three mirrors. Slow-mo is not essential but does help.
Visible crew/equipment: When Christine and Raoul are riding the horse out of the graveyard, it is obvious that Emmy Rossum has been replaced by a stunt double.
Audio problem: Right after Joseph Buquet is killed, Raoul runs and finds Christine. When she says, "Raoul, we're not safe here.", her lips do not move; her mouth is merely agape.
Continuity mistake: After being abducted during the Don Juan performance, Christine changes into the wedding gown and the Phantom places the veil on her head. The veil gets thrown aside by the time Raoul arrives. Between the time Christine leaves and the mob arrives, there is a shot of the mannequin with the veil perfectly positioned on the head (although it is highly unlikely that someone took time to put it back.) When Meg walks through the lair and retrieves the mask, yet another shot of the dummy shows that the veil has disappeared.
Continuity mistake: When Christine is in the Phantom's lair for the second time, after the Phantom puts the veil on her head, the camera has a close up of him (during the lines 'an eternity of this before your eyes') and the back of Chirstine's head can be seen not wearing the veil. When the camera pans back to her, she is wearing the veil and removes it a little later.
Continuity mistake: When Christine enters Carlottas dressing room after Hannibal, there are two stands of roses by the door. After she's changed there is only a small vase of roses, but the stands must have been way too heavy for her to move herself.
Deliberate mistake: As Christine approaches the Phantom in his lair (just after he has abducted her), we see that she is wearing very dark black eye-shadow. Back in the dressing room after coming off stage, as she talks to Raoul, we saw her face in close up and she was not wearing any eye-shadow at all, even though the Phantom leads her through the mirror just after she has managed to slip on a robe over her undergarments and she has not yet changed to go out to supper (Raoul says she is to be ready in 2 minutes). Her hair becomes 'bigger' and wilder, too. The change in her appearance is a reference to her descending (voluntarily, I might add - he didn't drag her through that mirror) into the Phantom's dark existence and to her sexual awakening.
Continuity mistake: During the scene where Meg is looking for Christine backstage, we see her pass Firmin and Andre. Behind her Raoul approaches the managers and they turn to greet him. In the next shot they are turned round flirting with the chorus girls, Raoul is nowhere to be seen, and Meg passes behind them again.
Continuity mistake: In the last part of the movie, when Raoul is all tied up, the Phantom pulls the rope around his neck, and mucous comes out of Raoul's nose. The camera turns, and then goes back to him, and the mucous is gone.
Continuity mistake: After "Think of Me", Meg is pushing through the crowd backstage, searching for Christine and she finally makes her way out of the crowd. Their actions repeat in a shot from a different angle. The next shot is a close up of Andre sharing a cigar with a woman and in the background, you can see Meg pushing through the crowd again, even though she already passed Andre.
Continuity mistake: As Christine and Raoul race up the stairs of the Opera House, her hair is loose. By the time they come out onto the rooftop, it's partially pulled back in an elaborate fashion. She's never off screen long enough to have done that.
Continuity mistake: When Christine first enters the Phantom's 'lair', one perfectly shaped lock of hair is on her left shoulder. Then, throughout "Music of the Night", it gets thinner, longer, and less curly two or three times. Then it goes back to its original thickness, length, and amount of curl.
Continuity mistake: When Christine is taken to the Phantom's Lair the first time (at roughly 38 minutes into the film), as the Phantom sings, he leads her by the hand from the gondola to the "Christine" mannequin. On their way, near the pipe organ is a Roman-style bust of a man's head with a dark strip of cloth askew over its left eye. When the Phantom sings "Let your soul take you." and "Savor each sensation." the strip of cloth is wide (like a sweat band), but when he sings "Let the dream begin." a 10th of a second later, the cloth has become very narrow - thin, like a bow tie. It turns back into the sweat band version again after Christine's nap.
Continuity mistake: At the end of the music of the night scene, the Phantom lays Christine down on the bed and sings the line, "help me make the music of the night." While singing this, he moves his finger down Christine's jaw line, and his finger comes off her chin. Yet when the camera angle changes, he is just starting to move his finger down her jaw, starting up near the ear. He wouldn't have had time to move his finger back up that quickly.
Other mistake: During the gypsy fair, when the young Phantom is hurriedly pulling the bag back over his head, you can see the actor's face from the side, through the bars of the cage. There is no deformity, even though the angle of the shot shows the top right of his face, where the mask is always worn later. Even moreso: his deformity is bumpy, and the side of his face is all baby smooth.
Audio problem: When Christine and Raoul leave the lair, singing to each other, she turns her head back toward the Phantom as we hear her singing 'each night, each morning,' but we can see she isn't saying anything: her mouth and lips aren't moving. It can't be that the Phantom is remembering the rooftop scene, because you hear the voices echoing in the cave, resonating differently as they move away. This is confirmed by the screenplay (p. 140 of "The Phantom of the Opera Companion"), which states that the Phantom hears them singing in the distance.
Factual error: Raoul is the Vicomte de Chagny and he gets called that throughout the movie, even during the auction (which shows he didn't change titles when his parents or his brother died, for example). Yet Christine's tombstone calls her a countess when it should have read viscountessor, even better, vicomtesse.
Visible crew/equipment: During the graveyard swordfight, the Phantom's stuntman sometimes visibly replaces Gerard Butler. He has thin and very arched eyebrows and the mask doesn't fit properly around the nose. He is the same stuntman used when Raoul jumps down the hole after the Masquerade.
Continuity mistake: In the last scene, Christine pulls the cover off one mirror. The coverings stay like this till the Phantom leaves, when both mirrors are uncovered.
Continuity mistake: After Think of Me, when Christine is in the chapel, it shows her light a match on a candle, then use the lit match to light the candle next to it. In the following shot, the camera shows all of the candles on that stand-only one is lit.