Continuity mistake: When the police confront Leeloo on the side of the building, she raises her hands and we can see that they're covered in soot. She jumps off and lands in Korben's cab. When she comes to, she presses her hand against the glass, and her hand is magically clean.
Revealing mistake: Right after they "create" Leeloo and she is lying in the plastic cage with the little straps on her, the guy approaches her and says, "if you want out, you are going to have to work on your communication skills." She gives him a dirty look, and then you can see a huge hole, pre-cut in the glass, that she busts her hand through.
Continuity mistake: When Zorg is first seen walking, and the screen only shows his legs, there is an audible clank as he steps with his RIGHT leg. After that, the clank is heard from his left foot.
Continuity mistake: When the police are chasing Korben and Leeloo in the taxi, Korben uses a video display map of "Manhattan 2nd District". When he switches it on, it looks normal, but when the camera cuts away then back again, the display is reversed as though it were in a mirror.
Continuity mistake: In the scene in the beginning when you first see the fifth element, and the camera moves up so you see the wide open mouth, look to the shoulder on the left. In the years of undisturbed dust, there are a few finger prints.
Continuity mistake: After Leeloo fights the Mangalores in the Diva's room but then has to give the stones box to Zorg, she throws it to him with forward rotation but when the box is shown flying through the air in slow motion, it's rotating backwards.
Continuity mistake: When the cops go looking for Korben and Leeloo in the fog, there are two orange light sticks hanging from the ceiling inside their car. From the outside looking in they are swinging from side to side very quickly. But from the inside looking out they are swinging from side to side very slowly.
Continuity mistake: When they are trying to place the stones in the temple, Korben picks up either the water or air stone - by the time they get to the plinth he's holding the fire stone.
Audio problem: When the stewardess is telling the people that she's putting on the sleep regulator, they show a different shot, and you see in the background she's mouthing words that don't match up.
Other mistake: When Leeloo escapes onto the ledge and goes around the corner of the building, there are people walking across a small bridge. One of these people vanishes in the middle of the bridge when walking to the left.
Continuity mistake: When the techs are analyzing the dark planet right before the first attack, the first tech turns to the second to report the sudden drop in surface activity. Between that shot and the following one on the second tech, the first tech's hand jumps from at his side to rising in front of his chin.