That is a good question.
If we knew the answer, we could meet the challenge better. Generally speaking, francophone immigrants have a tendency to settle in Quebec. It is not easy to persuade francophone immigrants that they can settle elsewhere than in Quebec.
Previously, selection programs favoured immigrants who spoke one or the other of Canada's two official languages, without distinguishing between them. There was no measure at that time for favouring applicants who had French language skills, even though not very many francophones settle in most of the provinces, except New Brunswick. In my opinion, our main challenge in terms of immigration outside Quebec is to make a chink in the wall that keeps francophone immigrants attracted to Quebec.