California Code, Public Contract Code - PCC § 22197

(a) The negotiation process shall expressly prohibit practices that may result in unlawful activity, including, but not limited to, rebates, kickbacks, or other unlawful consideration.

(b) The negotiation process shall expressly prohibit city employees from participating in the selection process when those employees have a relationship with a person or business entity seeking a contract under this chapter that would subject those employees to Section 87100 of the Government Code.