Legal Question in Landlord & Tenant Law in California

No, and there probably is no such law in NJ either. I know of no law in any state that entitles a tenant to get their rent money back. Most states, including CA haver laws that say a tenant can refuse to PAY rent, if a unit is uninhabitable, but the proof of uninhabitability is pretty high and generally requires a citation by code enforcement or a public health agency, and even then depending on the severity of the defect the tenant may owe the rent once the condition is fixed. As for illegal conversions, in CA and everywhere I know of, that is an issue of fines and penalties, and perhaps an order to remove the unit from rental use, between the landlord and the government; it does not give the tenant any right to do anything except possibly some claim for moving expenses and related costs/losses if the unit is ordered off the market.