Ironically, there are french-speakers in both of those areas. Montreal has seen several exoduses since the 1960's, in some part because of language laws, but a shift in the Quebec economy has been the issue of late. During the language issues/constitutional issues of the late 80s, many bilinguals moved across the border into Ontario. Previously, many bilinguals moved out of Quebec after the October crisis (though mostly Anglo-as-a-first-language).
Quebec's economic issues can't be ignored. Toronto is currently seeing a big influx of French speakers coming here for the "decent jobs". Even entry-level call bi-lingual call centre jobs are being moved here. Air Canada too moved some of their operations to Toronto this year.
An article on the exodus phenomenon here:
http://o.canada.com/news/francophone-migration-leaving-quebec-for-jobs/