Because of the mature content, I didn't think they would make the game like the movie, but have been very curious about what they would do with it.
If you are thinking about the sex scenes, I can tell you that the character of Jill (the woman with blue hair) didn't appear in the graphic novels until the second one (the movie compressed two stories into one). So probably the game designers won't have to worry about such things too much... until they start working on the second game.
I've only seen the movie. Looks like the screenshots are in the same Art Deco style. I can't remember the story so much as the incredible visuals - a hovering Pyramid over Paris - and that's probably what attracted Benoit Sokal.
Bilal is a legend of french-language graphic novel, much much bigger than Sokal ever will be. So I guess that's the main attraction of making the game.
Also, I've read in some interview with Sokal that they're pals and Bilal was looking for means to make a game, so he went straight to Sokal.