The landlord has a right to require every occupant of the apartment over the age of 18 to submit an application prior to moving in (or after they have been discovered living in the premises). Should the landlord request your boyfriend submit an application or provide basic information about himself and he refuses, the landlord may evict him as an unauthorized occupant and potentially evict you for housing an unauthorized occupant if it is in breach of your lease agreement.
This response is for informational purposes only and does not form an attorney-client relationship. It represents only the educated opinion of the author. It should not be relied upon as legal advice. The response is based on the limited facts provided, and might change given additional or different facts. Responses are based on CA law unless otherwise stated. Please contact a local attorney specializing in this area of law for more specific guidance.