At the bottom of Jeremey's computer screen, there's a series of seven weird-looking symbols. These symbols are letters from an alphabet designed for Star Wars: Episode IV - A New Hope (1977) called Aurabesh.
Code Lyoko transfer from 2D to 3D inspired the crossover of Jimmy Neutron and Timmy Turner in the Jimmy Timmy: Power Hour.
Aelita's eyes are green. The eyes of all the other characters are black. Also, in the second season, Aelita's eyes are black while not in LYOKO.
The shots of Ulrich, Yumi, and Odd in the scanners was recycled from the five minute short that inspired the series.
The name of the martial art that Ulrich, Yumi and Sissi use is Pencak Silat, also known as Silat.