It is not intended, by this chapter, to repeal, abrogate, annul or in any way to impair or interfere with existing provisions of other chapters, ordinances, except those specifically repealed by this chapter, or with private restrictions placed upon property by deed, covenant or other agreements. However, where this chapter imposes a greater restriction upon the land, buildings or structures than that imposed by existing provisions of chapters, contract or deed, the provisions of this chapter shall control. Where the provisions of this chapter are, or become, in conflict with State or Federal law and such differences cannot be reconciled therewith, the provisions of such law shall govern.