The leader of the Parti Quebecois wants stronger, tougher language laws that would affect would-be immigrants.
The proposals are a reaction to the 2016 census which showed an increase in the number of allophones and anglophones in the province.
The census showed an overall increase in bilingualism, and that knowledge of the French language in Quebec is stable at about 94 percent, but the ratio of people with French as a mother tongue, or who speak French at home, has dropped.
The results are being questioned, in part because of the controversy around the 2011 census and the long form, which was not mandatory, and the sample sizes in rural Quebec.
Jean-Francois Lisée said there are questions, but in his opinion it is clear that there are fewer mother-tongue francophones in the greater Montreal area.
His answer to that problems would come three months into a mandate
"Bill 202 would be introduced in the first 101 days of a PQ government," said Lisée.
If elected as the leader of the provincial government next year, Lisée would oblige all future immigrants to demonstrate they have a good knowledge of French.
He would also require all federal companies in Quebec to operate in French, and likewise for medium-sized companies.
The proposed Bill 202 would also require students at English-language CEGEPs and universities to pass a French test before graduation.
"If you want a degree of high education in Quebec, in a place where things are going in French, I think it's just basic decency for society to give you a tool for success and one of those tools is to be proficient in French," said Lisée.