When conflicts between ruling powers came to an end, they were often settled by the signing of a treaty. As part of this, it was common that geopolitical boundaries changed, and in some case control of specific cities. Assuming a large chunk of the population of a given city (say, businessmen or artisans) was not directly involved in active conflict, which would in any case have ceased by now, how would their life have changed in the aftermath of a treaty being signed?

Example: Say I'm French and I live in a part of Canada that's changed hands from the French to the British after the Treaty of Paris in 1763, and I'm mostly minding my own business and getting on with my job. Do I go back to France, or to the nearest French-controlled territory? Or do I just get on with things and work with the new administration? Are British people hostile towards me just because I'm French? Do I need to learn English now?