If you have a problem with your mouse in the game XIII, then this is what worked for me:
Change your mouse settings in windows so that it is at its minimum possible sensitivity. To do this, go to Control Panel | Mouse | Pointer Options (tab) | Select a pointer speed. Move the slider to the absolute left, so that it is as slow as it can get. Then crawl your mouse over to your XIII icon and play. The game should be fine now. This obviously doesn’t solve the problem, since you have to change the setting back in order to use windows, but it is certainly a work around. After changing this one setting I was able to play XIII.
I don’t know if this makes any difference, but some people suggest that you turn off ‘Enhance pointer precision’. This alone made no difference to me.