This chapter shall not be deemed to affect in any manner whatsoever any easements, covenants or other agreements between parties; provided, however, that where this chapter imposes a greater or lesser restriction upon the use of buildings or land or upon the erection, construction, establishment, movement, alteration or enlargement of buildings than is imposed by other local laws, rules, regulations, licenses, certificates or other authorizations or by easements, covenant or agreements, the more restrictive requirement shall prevail.