During the opening musical number, Big Daddy holds up a newspaper while in the car revealing a number of headlines including "Ford Corporation Introduces Trimotor" and "Gertrude Ederle Readies to Swim the English Channel." Neither of these events, nor Mardi Gras for that matter, took place on the newspaper's supposed date of April 25th 1926. The Trimotor first flew in June 1926, Ederle wouldn't swim the English Channel until August 6th, and Mardi Gras in 1926 fell on February 16th.
When Prince Naveen prepares the romantic dinner, he leans over the improvised table, and falls. However, only seconds later he gets up and sits on the edge of the table, which this time supports his full weight.
During the song "Friends on the other side" Dr Facilier spreads the cards from right to left. After a cut to Prince Naveen's face the cards have switched directions as if spread from left to right allowing him to flip them over the way he did.
The first time the brunette and the blonde are seen clapping along with Naveen's performance, the brunette is wearing a lot of jewelry. However, the second time they are shown, some of the jewelry is gone.
Louis is established to be an alligator in the film. But when an alligator's mouth is closed, its teeth do not show out like a crocodile's. In the shots where Louis's mouth is closed, his teeth are showing.
Tiana is left-handed, but sometimes uses her right hand for writing and kitchen work. For much of European and American history, society considered using the left hand to be sinful or unnatural, so "lefties" often felt compelled to use the right hand in polite company.
On several occasions (particularly in "Almost There" and at the ball), there are numerous people either drinking or holding glasses of wine or champagne. This movie is set primarily in the 1920s. The possession and sale of alcohol in the United States was illegal between 1919 and 1933, because of the 18th Amendment (Prohibition), though Prohibition was widely disregarded, especially in New Orleans.
After Dr. Facilier retrieves the talisman from Tiana he turns her back into a frog and pins her down with his cane. The cane is there but after she grabs the talisman with her tongue the cane disappears and is nowhere to be found.
The newspaper at the beginning of the movie talks about Naveen's trip to the states and reports that the small obscure country sent their only son. At the end of the movie in Tiana's Palace Charlotte is dancing with Naveen's six and half year old brother.
In the beginning of the movie, Tiana's dad writes "Tiana's PLACE" on the picture. At the end, the menu reads "Tiana's PLACE", but the restaurant is named "Tiana's PALACE". This deliberate name change is to emphasize the fact that Tiana is now a princess.