WI for some reason (if you find a good PoD, I'd be interested to hear about it), revolutionary France (and the Empire, if it exists, and all successor régimes) never set out to conquer and/or reform Europe, and left the Ancien Régime undisturbed. How would the XIXth century unfold in such a TL?
Especially: would there be a mediatisation in the HRE, and if yes, when and how? How does this affect the industrial revolution? What would be the fate of the Austrian Netherlands (I really can't see that one lasting, but who knows)? Do Germany and Italy still unify?