Plot hole: When Charlotte kissed Naveen at the end, she should've turned into a frog as well because she was no longer a princess.
Suggested correction: When ordinary people kiss a frog, they don't transform into anything. (Perhaps they die from infection after a few days.) Charlotte was just an ordinary person. Tiana was chosen. She wished upon the star. Naveen and the consequences of kissing Naveen were a result of Tiana's wish.
Suggested correction: How? She was no longer a princess.
Tiana turned into a frog because she kissed Naveen without being a princess, so Charlotte should have, too.
Continuity mistake: The poster that Tiana has that her father wrote on says "Tiana's Place." When she finally gets her restaurant, the name is "Tiana's Palace" yet the menus still say "Tiana's Place." (01:29:00 - 01:30:00)
Continuity mistake: Near the end, Dr. Facilier has Tiana pinned down with his staff. After Tiana uses her tongue to grab the talisman from Facilier's hand, the staff is no longer anywhere to be seen.
Continuity mistake: Tiana wears a pair of gold earrings during Charlotte's ball. They disappear when she's watching Charlotte dance with the prince and reappear later. (00:23:55)
Other mistake: Charlotte's dad buys a newspaper in the beginning of the film. The same two paragraphs about Prince Naveen are repeated all over the front page, including under the headline 'Annual Goosenhoper State Gumbo Faire Is Smashing Success.' (00:08:45)
Factual error: The alligator mentions wanting a Bananas Foster. This dessert was invented in 1951 but this movie takes place in 1926.
Other mistake: When the old woman is cooking gumbo in a large bathtub, it's shown boiling and really hot. Yet the two frogs can sit right on the rim of the bathtub inches above the boiling food in a non insulated tub without getting burned or even hot.
Continuity mistake: As Tiana and Naveen are floating over the swamp hanging onto the balloons, the amount of balloon strings alternates between three and four stings depending on the angle. Most of the time, when the shot is on Tiana there are three strings and when on Naveen there are four. (00:33:00)
Continuity mistake: Hoping to turn Naveen from a frog back into a human, Charlotte kisses him seven times, leaving seven sets of lip prints around his mouth. He remains a frog, but in the next shot, all the lip prints have suddenly vanished.
Continuity mistake: When Lawrence finds Naveen playing with the local jazz band, we see three young girls standing together on the left. Then a few shots later, two are standing together with a different lady who switched places with the third young lady (the different lady is tall and has weird looking feet).
Continuity mistake: Tiana and Naveen have been turned into frogs. They go to see Mama Odie, hoping she can turn them back into humans. She holds out a giant pearl and the frogs are reflected on the surface, but in the reflection the frogs have switched positions.
Continuity mistake: When Tiana is told she was outbid, the real-estate agent in the head of the horse costume turns her through the middle of the two parts of the horse costume. A few seconds later you see the two agents get back in their costume and walk off seamlessly.
Continuity mistake: When Dr. Facilier transforms Tiana back into a human to offer his deal, she is wearing a white dress with a large feather boa around her arms. When Tiana turns to the ukulele player whom she thinks is Naveen, the feather boa falls off her and is never seen again during the rest of her temptation.
