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. (01:15:25)
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. (01:53:15)
Continuity mistake: When Korben lets his cat in the apartment, the cat jumps up onto the bed and watches the TV. Korben is then seen dealing with the hoodlum and when he turns to put the gun in the rack, the cat is gone and the bed is back in the wall. (00:19:25 - 00:20:25)
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.
Continuity mistake: The pre-cut piece of glass that Leeloo breaks through when she escapes is a different shape after it is broken.
Other mistake: When the two police officers are searching for Korben's taxi, as one police officer asks "How do they expect us to find anything in this... ", both police officers have the same ID number on their helmets. (00:39:15)
Character mistake: When the police scan Leeloo the first time, the computer reads "Commencin" instead of "Commencing."
Continuity mistake: When the technicians are changing the radioactive fuel of the shuttle, they find shaking bugs and start to burn them. The bugs aren't shaking in one shot. (01:17:10)
Continuity mistake: During the missile barrage on the dark planet, one of the soldiers says, "The planet has increased in diameter by 200%." That means that the diameter would be triple the original size, but it's obvious from the missile impact animations that it hasn't grown anywhere near that much. (00:16:30)
Continuity mistake: As Korben and Ruby ascend the stairs to the opera house, during the chase shot we can see all of their backs, but both before and after there are people behind them that would make this impossible. (01:26:20)
Continuity mistake: When David is waiting for the priest and Leeloo before attempting to board the shuttle to Phloston Paradise, he is chewing on the nail of his index finger. The shot changes to show a different angle of him and he is now chewing on his thumbnail with no time for him to have changed position.
Revealing mistake: When the doors of the temple close on the Mondoshawan, it shakes like styrofoam.
Revealing mistake: When the bomb that Korben puts on the balcony explodes, there are two quick shots of the Mangalores. They are dummies because they've stopped shooting and don't move. (01:42:10)
Continuity mistake: When Billy trips on his equipment bag, he fires the gun in an arc that goes up and slightly left. The sparks on the alien go from the center up and to the right.
Character mistake: Right before the door of the tomb closes and traps one of the Mondoshawans inside at the beginning of the film, the Priest says "hurry, you still have time". But there is not enough room left for the Mondoshawan to squeeze through.
Continuity mistake: As Leeloo gets off the ship at Fhloston Paradise, in one shot she is looking slightly to her left and in the next shot from behind she is looking to the right. (01:22:40)
Continuity mistake: The shadow of the dark planet is heading in the direction of the sun, instead of away from it, in the scene where the dark planet is approaching the temple. (01:54:55)
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.