Legal Question in Landlord & Tenant Law in California

It might or might not be illegal, since it might constitute sexual harassment. Unless the landlord is your spouse, the landlord might be violating the implied covenant in your rental agreement of quiet enjoyment of the premises. Have a discussion with the landlord and express your concerns. If the landlord won't change, you might claim your rental agreement has been breached, and you should be able to move without penalty. You might also pose this question to the California Department of Fair Employment and Housing.