As you know it is very acceptable to relocate for a shidduch, and for the wife to follow the husband.
But that doesn’t mean that it is not hard, or whether you can handle it. Maybe this will help- rather than think about what you will miss/lose out by marrying him and moving to Montreal, think about it the other way- what will you miss/lose out on by staying where you are and not marrying him?
Such a decision is easier to make for someone who has been dating for a long time, or who has a particular reason to think finding a suitable shidduch is hard. But we don’t know what your circumstances are.
Something else – considering the state of France these days and that a lot of Jews are leaving, can you be sure that all of your family will stay in one place? even if you marry a local, it doesn’t mean you will stay in France.
When I was dating, I once ended a shidduch over the issue of where to live. But I don’t think that was really the main reason- if he had truly been the right one, I would have been willing to relocate for him, it became a big deal for me because somehow I knew he was not right for me.