Legal Question in Real Estate Law in California

Neither one of them have a fiduciary duty of any kind to you. The company MAY have a fiduciary duty to the third party, but that is nothing to you.

The owner has a duty to you to provide habitable premises.

The landlord and his agent do not owe a "fiduciary" duty to you, unless there is something that you are not telling us about. (The only situations that I can think of is where the landlord's agent is also your real estate broker, or is holding a security deposit for you in a trust account pursuant to a rent control ordinance.)

A duty to provide habitable premises is not, however, fiduciary in nature. Leasing or property-management companies may have fiduciary duties to their principals (the property owners), but not to tenants - except perhaps in the unusual circumstances Mr. Roach suggests.

What everyone above says is true, but I suspect yo may not know what a "fiduciary duty" is. Duty means that there is a legal obligation to behave or not behave in a certain fashion to another. A parent owes a duty to their child, a vehicle driver to their passengers, and even a motor vehicle driver to others using the streets they both are using. But what you do in your house does not impose any duty on you to me. If what you are doing is preparing a bomb, you do have a duty to me not to set it off so as to injure me. Fiduciary means related to money or anything of value. So if I give you money to invest for me, you owe me a fiduciary duty to act reasonably as to that money. A landlord owes a fiduciary duty to a tenant as to the tenant's security deposit in that the landlord must return it, absent failure to pay rent or damage to the property. But a landlord, absent some special circumstances owed no such duty to the tenant, nor the tenant to the landlord, although they do have other types of duties to each other.