While walking in a park, an extra passes Jesse and Celine. When the camera angle moves to their front, he passes about 10 seconds later.
When Celine and Jesse are entering Celine's apartment, she opens a "right hand" door, the next shot (from the inside) shows her opening a "left hand" door. It is not the same door.
When Jesse and Celine walk from the book signing to the cafe, the couple they pass window shopping is wearing different clothes depending on the camera angle.
When Jesse and Celine sit on a bench in the park Jesse has his arm around Celine in one shot, in the next his arm is gone.
A change in street scene: when Celine tells Phillippe that they have arrived at her apartment, the view through the back window is of one way traffic, but when the car does pull over and they get out, the traffic is two-way.
When Jesse and Celine are walking through the park after they have had coffee, a leaf falls from a tree, unscripted, and catches Ethan Hawke's eye, but the camera continues to roll.
When Céline and Jesse are at the Café, a wire (of a microphone) is visible in Jesse's shirt.
When the taxi pulls up into Celine's apartment, the cameraman is reflected on the side and back view of the car.
Camera shadow visible as Jesse and Celine head up a flight of stairs.
The boat on the Seine, moves to the east, but in one shot, the boat moves to the opposite direction (The Eiffel Tower is clearly visible, which means the boat travels to the west). The differences between shadows and no shadows on the wharfs of the Seine are also indicating this.
The girl explains that the cat's name, "Che," is not inspired by Che Guevara, but rather by the Argentinian expression for "hey." However, Guevara's nickname happens to be the very same word that Argentinians use to say "hey."