Okay, so the ingame options lets you change two settings, Camera Control and Look Mode. Camera Control seems to work, in that it flips the Y-axis if set to Reversed, but the Look Mode setting appears to flip both the X and Y-axis, which is completely useless. Is there any way to flip just the Y-axis for normal looking around?

I had a dig about in the beyond good and evil forums and found this thread [url=]http://forums.ubi.com/eve/forums/a/tpc/f/401101532/m/286101532/p/2[/url] aparently its been a problem since the game came out with no offical fix.
Some guy took it upon himself to program a mouse driver for it though http://www.maf-soft.de/mafmouse/ I haven't used it myself, so its at your own risk but it might work.

Seriously, this is the most ridiculous bug I've ever seen. The arguments in the thread you linked to, that it was a conscious design decision by the developers, is totally unbelieveable. For me, right now, the game is unplayable. I may try that driver tomorrow, but it's not free, and I can't believe I have to buy third-party software to be able to play this game.
It's worth noting that the top 4 on the list of games needing this driver are all Ubisoft games. Ubisoft, you suck.