The French Revolution and Napoleonic France are seen by a lot of historians as the beginning of mainstream French nationalism, so if Rev. France triggers shouldn't a melting pot French culture spawn with it? Just a suggestion.
Too much work for an event that's unlikely to happen, and even if it does fire the game only has a few decades left anyway.
Even looking past that, the large-scale assimilation of the regional 'French' languages (Occitan, Breton, etc.) did not occur until well into Victoria 2's timeline, let alone EUIV.
It started during the revolution by the Ordonnance of Villers-Coterêt.
http://en.wikipedia.org/wiki/Language_policy_in_France
The revolution was the mean to centralize the political forces in Paris and put forth the ultimate reforms mandatory.