I thought I had found something along these lines when I discovered Internal Collonialism, but it ended up being something about unequal development today - or maybe I'm wrong?
But I'm wondering why the distinction's made between gradually expanding authority over formally independant groups and places (Brittanny, Aquitaine, Burgundy...) is differ from Collonialism. Isn't it more or less the same? I'm also familliar with the debate on whether or not Roman expansion can be called Collonialism and though I' still don't really understand the arguement against it, would this expansion of Nation-State-Authority be more similar to that then?
I just picked random examples. But really, any authority expanding (Persia, the Mughals, Prussia into Kleindeutschland, Russia, Modern Italy and so on vs. any collonial regimes would work.) Only in the cases of say Haiti or Australia, can I see a big difference, replacing the population and never with the intent to incorporate them (unlike the Spanish in Mexico who honored Aztec nobility...) and populated a mostly empty region (at least I believe the Australian coasts were mostly empty, though I am aware of the tragedies acted against the natives but... There were also genocidal events in Europe, weren't there?)
So... Can't William the conquerer be called a Collonist, or any other successful invader?
So, i'm not sure I completely understood your question, but here goes : how was France's continental expansion different from its colonial expansion?
So the main issue here is that France's (or Paris as you mention - though through things like inheritance of titles and lands it is not quite that clear-cut) expansion was done over a very long period of time. In fact when you look at the global picture a strong case could be made that the country's continental expansion was mainly done through diplomatic means (marriages, exchange of favours, and slowly acquiring the nobles' vassalage). Another important point is that the king ruled through divine right - meaning support of the Pope, which was helpful in integrating new catholic populations.
Now if you consider French colonies, most were acquired through force of arms (the case of Morocco being a bit different, same for canada, etc). I would postulate that the main difference between colonies and the mainland was the status of it's citizens. All inhabitants of continental France were given the same rights, while those coming from the colonies were in a sense second-class citizens. This becomes even more evident when the nation became a republic. No right to vote, no right to hold office, and basically no real representation. Keep in mind that for a large part of the french population these people were savages, and France was gracefully 'enlightening' them.
So to sum up, colonization was done very fast, mainly through military conquest, and segregated the conquered population while the continental expansion was much slower overall, included much more diplomatic bargaining, and gave the new populations equal (or close to) status with the existing citizens.