Mostly, they reach the same people you have already contacted.
The problem with general boards
Indeed, LinkedIn and Job Bank have Canadian audiences. Post a role requiring French and you reach French speakers already in Canada — the pool every other employer in your city is also competing for.
If local recruitment has already failed, posting again on the same platforms rarely produces a different outcome.
The supply problem underneath
Roughly one in five Canadians speaks both official languages, and outside Quebec and New Brunswick the proportion of employers requiring bilingualism is small but the candidates are scarcer still.
Bilingual postings also attract fewer applicants than single-language ones, because the requirement filters out most of the market before anyone applies.
Where the candidates actually are
Canada's own guidance points employers toward France, Belgium, Morocco, Tunisia, Côte d'Ivoire, Senegal and Mauritius for French-speaking recruitment.
Those are large French-speaking populations with significant numbers of people actively interested in working in Canada. They are simply not on Canadian job boards.
What reaching them requires
A platform with audience in those countries. Not a Canadian board with an international filter — a site people in Casablanca or Abidjan actually visit.
The other variable: how they apply
In several of those markets, mobile and messaging apps dominate. A posting that requires an account and a desktop form loses applicants that one accepting WhatsApp does not.
FrancoBridge publishes to candidate portals in Morocco, Tunisia, Côte d'Ivoire, Cameroon and Mauritius, alongside Canada, with WhatsApp and quick apply.
This is general information for employers.