The ownership, right of control and use of the streets, highways, alleys, parks, public places and all other real property of the City is hereby declared to be inalienable, except by ordinances not in conflict with the general laws of the State of Texas, duly enacted by the City Council of the City. No franchise or easement involving the right to use same, either along, across, over or under the same, shall ever be valid, unless expressly granted and exercised in compliance with the terms hereof, and of the ordinances granting the same. No act or omission of the City, its City Council, officers or agents shall be construed to confer or extend by estoppel or indirection, any right, franchise or easement not expressly granted by ordinance.