Well, by 1814, he's already in his majority, which could change how the Congress of Vienna handles things.
Assuming not much else changes and Napoleon I still ends up losing, Napoleon II might get some land in Italy (Probably in the Austrian sphere of influence). This, of course, completely messes up French politics afterward, since Napoleon III no longer has a legitimate claim as the Bonapartist candidate if Napoleon II is still alive.
How things develop though depend entirely on Nappy II's character. If he gets land in Italy, might he take up the mantle and unify Italy instead of Piedmont (unlikely, I know)? Or does he take Nappy III's place in France (equally unlikely)?