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. (00:29:47)
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. (00:32:35 - 00:33:20)
Continuity mistake: When the cops are are getting the Golden Menus, the girl at the drive-in window hands them their order and you see a multipass on top of one of the boxes. The cop in the passenger seat gives the driver the order and the multipass is gone. (00:36:50)
Other 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. (00:09:35)
Continuity mistake: In the beginning at the Egyptian temple while speaking to the Priest, the Professor has his cup in his right hand then a brush then the cup again...all while speaking the same sentence. (00:05:35)
Visible crew/equipment: Just after Korben escapes from the police, you can see a reflection of a crewman in a blue T-shirt on the windshield.
Continuity mistake: When Leeloo jumps from the building, the elevator track, which was attached to the building on her right-hand side, has vanished. (00:30:10)
Continuity mistake: When Billy shouts at the Priest while holding the gun, there is a tripod standing behind Billy to his right. Billy yells, "Don't move." The shot changes to the Priest and then back to Billy again when Billy says, "I have a gun" you notice that the tripod behind him has disappeared. The tripod reappears in the overhead shot where the Priest says, "I'll explain everything." (00:11:00)
Continuity mistake: At the beginning of the film, when the door of the tomb is closing on him, the Mondoshawan extends his arm to give the key to the priest. His hand is completely out but the shot later, only the end of his fingers are outside. (00:11:50)
Continuity mistake: When Zorg's henchman is on the phone with Zorg and Zorg blows him up. As the smoke clears and the fires die down, the body of the henchman is still standing at the phone. (01:18:55)
Continuity mistake: When LeeLoo is on the ledge outside of the building, the police corner her & take her picture. Her face is pretty calm, but when the picture is developed on the police screen, she looks shocked. (00:32:20)
Continuity mistake: When the priest is telling Billy to put down the gun, the camera angle from the back shows his left hand making the motion to put the gun down. The camera angle changes to the front and his right hand is now making the motion. (00:11:20)
Revealing mistake: When the space ship leaves the Earth's atmosphere about to make the jump to Phloston Paradise, you can see the box around the spaceship used as part of the effects process.
Answer: I looked it up and it is Jill Milan. If you do a search for her, it is in her credits as an actress.