Speculation can lead us everywhere.
Both Massena's proclamation to the Portuguese in 1810 and Wellington's to the French in 1813 are very similar.
The difference is that while Wellington did everything to make it so, Massena eventually couldn't or didn't want to make it so. Of course Wellington was pushing in succesfully, while Massena was blocked out in Torres Vedras. Even so, Wellington risked and let loose some thousand Spanish troops and superiority of numbers, before he pushed further into France.

Anyway, at a certain point, the French people prefered to supply the Anglo-Portuguese, rather than their own army, thus creating some antagonism between the army and the people. This might indicate, among other things (the British bought, the French requisitioned), that the French people was receptive, as well as, in the contrary, the Portuguese people (after 1807-1809, and 2 invasions) were not.

My post is outside any claims of imperialism either French or British.

Jorge