No landlord may threaten to bring, or bring, an action to recover possession, cause the tenant to quit the unit involuntarily, serve any notice to quit or notice of termination of tenancy, decrease any services or increase the rent where the landlord’s intent is retaliation against the tenant for the tenant’s assertion or exercise of rights under this chapter. Such retaliation shall be a defense to an action to recover possession, or it may serve as the basis for an affirmative action by the tenant for actual and punitive damages and injunctive relief. In an action by or against a tenant, evidence of the assertion or exercise by the tenant of rights under this chapter within six months prior to the alleged act of retaliation shall create a presumption that the landlord’s act was retaliatory. "Presumption" means that the court must find the existence of the fact presumed unless and until its nonexistence is proven by a preponderance of the evidence. A tenant may assert retaliation affirmatively or as a defense to the landlord’s action without the aid of the presumption regardless of the period of time which has elapsed between the tenant’s assertion or exercise of rights under this chapter and the alleged act of retaliation. (Ord. 5467-NS § 14, 1982: Ord. 5261-NS § 14, 1980)