California Code, Probate Code - PROB § 2403

(c)(1) When a guardian or conservator petitions for the approval of a purchase, lease, or rental of real or personal property from the estate of a ward or conservatee, the guardian or conservator shall provide a statement disclosing the family or affiliate relationship between the guardian and conservator and the purchaser, lessee, or renter of the property, and the family or affiliate relationship between the guardian or conservator and any agent hired by the guardian or conservator.

(2) For the purposes of this subdivision, “family” means a person's spouse, domestic partner, or relatives within the second degree of lineal or collateral consanguinity of a person or a person's spouse. For the purposes of this subdivision, “affiliate” means an entity that is under the direct control, indirect control, or common control of the guardian or conservator.

(3) A violation of this section shall result in the rescission of the purchase, lease, or rental of the property. Any losses incurred by the estate of the ward or conservatee because the property was sold or leased at less than fair market value shall be deemed as charges against the guardian or conservator under the provisions of Sections 2401.3 and 2401.5. The court shall assess a civil penalty equal to three times the charges against the guardian, conservator, or other person in violation of this section, and may assess punitive damages as it deems proper. If the estate does not incur losses as a result of the violation, the court shall order the guardian, conservator, or other person in violation of this section to pay a fine of up to five thousand dollars ($5,000) for each violation. The fines and penalties provided in this section are in addition to any other rights and remedies provided by law.