I don't think there is. U8's development came at a time when games were being internally internationalized (with language packs or some equivalent) at least some of the time, but in U7's era, if there were multiple languages used in development, they were generally compiled and packaged as completely different products, so you'd need to find a copy that was 'built' in French and GoG probably just doesn't have one (if one was ever done).
If you're familiar with modern English though then the stylized language used in the game (which isn't really Old English) shouldn't actually be troublesome since it's largely "take a couple of letters off to get the modern equivalent" (canst instead of can, dost/doth instead of do, etc) stuff. It mostly looks daunting (even if your first language is English!) rather than actually being difficult.