Can a certificate of occupancy be used as a defense to an action for unlawful detainer?

(4) Gruzen v. Henry (1978) 84 Cal.App.3d 515 [148 Cal.Rptr. 573] dealt with the same issue. There, premises for which no certificate of occupancy had been issued were leased and the landlord brought an action for unlawful detainer. The court stated "the question before us is whether [the ordinance requiring a certificate of occupancy], which is silent as to the effect on leases of a violation of its requirements, but expressly imposes only a criminal sanction on violation, can be construed as permitting enforcement by way of a defense to an action for unlawful detainer. We conclude that it can." (Id. at pp. 517-518.) The court then held that "[p]laintiff is entitled to an order of eviction, but not to an award of rent." (Id. at p. 519.)