What is a shareholder agreement and its usefulness?

Both in Canada and in Quebec, a shareholder agreement agreement is to protect the interests of the shareholders of a business corporation and prevent the intrusion of third parties among them. It governs the transfer of shares during the lifetime of the shareholders as well as at the time of death of those. Mechanisms are provided therein to prevent and resolve the discord. The shareholders also bind therein their vote so as to elect themselves as directors. An agreement signed by all the shareholders (being a unanimous shareholder agreement) can even be used to remove the powers of the directors of the business corporation to attribute them to the shareholders.