California Code, Government Code - GOV § 25527

If, in the discretion of the board, it is advisable to offer to pay a commission to a licensed real estate broker who is instrumental in obtaining any proposal, the fact that such a commission will be paid and the rate thereof shall be specified in the resolution.  No commission shall be paid unless the resolution specifically provides for the payment of the same and there is contained in or with the sealed proposal or stated in or with the oral bid, which is finally accepted, the name of the licensed real estate broker to whom it is to be paid, and the amount or rate thereof.  Any commission shall, however, be paid only out of money received by the board from the sale or rental of the real property.