Every grant of a franchise, right or privilege shall be subject to the right of the City Council, or the people of the City acting for themselves by the initiative and referendum, at any time, subsequent to the grant, to repeal, amend or modify the grant with due regard to the rights of the grantee and the interest of the public; and to cancel, forfeit and abrogate any such grant if the franchise so granted is not operated in full accordance with its provisions, or at all; and at any time during the grant to acquire, by purchase or condemnation, for the use of the City itself, all the property of the grantee within the limits of the public streets, at a fair and just value, which shall not include any valuation of the franchise itself, which shall then terminate; and every ordinance making such grant shall contain a reservation of these rights of the City Council, and of the people of the City acting for themselves by the initiative and referendum, to so repeal, amend or modify the ordinance, and to so cancel, forfeit and abrogate the grant, and to so acquire the property of the grantee in the public streets, as provided in this section.