I believe you are referring to an illegal garage conversion. If so, you should contact the Los Angeles Department of Building and Safety and the Los Angeles Housing Department to file a complaint. If it is unpermitted and unregistered, they may require the landlord to pay you relocation fees before you can be evicted. In addition, failure to comply with the Los Angeles Rent Stablization Ordinance is a possible affirmative defense to an Unlawful Detainer. Finally, you may be able to recover the illegally collected rent. Carter v. Cohen, 188 Cal.App.4th 1038 (2010).
An experienced landlord/tenant lawyer will know what defenses to present as well as how to present them. Even though there is no Certificate of Occupancy, one must present competent evidence at trial. There is a reason why lawyers attend law school for 3 years and must pass a bar examination. See the answer to a similar question posted a few moments ago.
Mr. Freitas is an attorney licensed in the State of California. The answer provided here is general information and not intended to be specific legal advice. There is not attorney client relationship created by Mr. Freitas' answering any question on this website.
If this is an illegal garage conversion, the landlord can still evict the tenant by filing an unlawful detainer lawsuit. There probably isn't much a lawyer can do to completely prevent the landlord from obtaining restitution of the premises. However, a lawyer might nevertheless be helpful in negotiating a favorable settlement.
The landlord will not be able to recover monetary damages for unpaid back rent or for holdover damages if the rental dwelling is illegal. A lawyer will be helpful in establishing that the rental dwelling was illegal for purposes of preventing a money judgment against the tenant.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This Avvo.com posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult with your own attorney.