Near the end, when Helen is wearing the red dress, Charlie comes home drunk and puts the chain on the door. The chain is a lot longer than a normal door chain. When Helen comes home later and tries to get in, the chain is now much shorter - the length of a normal door chain.
(at around 1h 30 mins) When Helen is hospitalized for the second time, an oxygen tent is rolled into her room, but when Charlie goes into her room the tent is nowhere to be seen.
At the beginning, Charlie arrives at a train station carrying a suitcase. He hails a cab. Shortly thereafter, he exits the same cab sans suitcase. It is not seen again.
After the race in Monte Carlo, a rain-soaked Charlie and Lorraine Quarl down a drink at the bar with their hair a watery mess. Then Charlie walks to the table where Helen and Paul are seated. A minute later, Lorraine joins him with perfectly dry, quaffed hair. This would not be possible even though she raised a comb to her hair while at the bar beforehand.
When Charlie sits down at the park on his first visit there with Helen, a balloon seller who was not there previously appears behind them.
In the title screen at the beginning of the the movie it says "COPYRIGHT MCMXLIV IN U.S.A.", which in roman numbers is 1944, but the film was released in 1954, in roman numbers would be MCMLIV.
The flashback originates from a newspaper headline reading "U.S. TROOPS IN PARIS", over a photo of American soldiers marching through the Arc de Triomphe. The newspaper headline and photograph date from the liberation of Paris in August 1944. This 1944 photo then transforms into the beginning of the flashback, which is set not in 1944 but on V-E Day (May 8, 1945).
This is not a Goof; 1944 occurred before 1945, and the flashback begins in 1945. The headline and photo are simply providing background.
This is not a Goof; 1944 occurred before 1945, and the flashback begins in 1945. The headline and photo are simply providing background.
Charlie and Helen are waiting to see the lights of Paris turn on when the large crowd starts singing a song in unison. There is a closeup of an older, grieving woman crossing herself by the War Memorial while a soldier and a younger woman behind her are singing along with the crowd, but their lips are not moving correctly with the lyrics.
(at around 38 mins) When Helen swings the baby in the air and says, "No guts, eh?", her lips aren't moving.