Quebec had two main reasons for not signing the agreement which brought the Canadian constitution: A constitution is the system of fundamental principles according to which a nation, state or group is governed.constitution home. With the new amending formula Quebec lost its veto: the right or power to forbid or reject; to refuse to consent to.veto over future constitutional change. Until then, Quebec or Ontario or a majority of Western or Maritime provinces could prevent any constitutional changes they didn't agree with.
Another reason Quebec wouldn't sign was a clause in the Charter of Rights which guaranteed minority language rights "where numbers warrant." This would have meant the end of Quebec's Bill 101 by protecting English language rights in Quebec (while at the same time protecting French language rights in the rest of Canada).