Immortel is based on the "Nikopol Trilogy" - mostly book 2: The Woman Trap. They make a bit more sense than the film, probably because you can take your time with them. But there's a lot of Eastern European political allegory going on, so it's foriegn territory for your average genre movie/FX fan.

I think Bilal was working on stuff for Heavy Metal/Metal Hurlant back when Ridley Scott was checking it out for Bladerunner, but Moebius would've been the greater influence on Bladerunner.

Bilal has a few other films out but it's hard to find subtitled versions - nothing with Immortel's level of FX though. Some interesting and surprising techniques - seemingly random use of real actors and CG ones. Definitely a unique piece.

Cheers