In Canada there is a constitutionally protected "freedom of conscience and religion". That right is subject to reasonable limits - and the courts have held those limits need to be narrow and focused on a significant and proper governmental objective. It seems most unlikely that the protection of Quebec values would be sufficient to justify, say, banning a priest from wearing a clerical collar during hospital visits.
That said, Quebec, as a province, can opt out of the constitutional protection by way of legislation expressly so doing - the notwithstanding clause of the Canadian constitution.
And that may be the very point.
The proposed legislation is silly. It is clearly intended to make religious minorities in Quebec feel unwelcome. As Justin Trudeau pointed out it makes Quebec a laughing stock. If passed it will be ruled unconstitutional - there can be little doubt of that.
But then the Quebec government can either override the Supreme Court of Canada or claim "we tried to protect Quebec culture and the Feds stopped us". Either way separatists emphasize a wedge between Quebec and the Rest of Canada.