S.F. Admin. Code ch. 37 § 37.11A

(a) Whenever a landlord charges a tenant a rent which exceeds the limitations set forth in this Chapter, retaliates against a tenant for the exercise of any rights under this Chapter, or attempts to prevent a tenant from acquiring any rights under this Chapter 37 , the tenant may institute a civil proceeding for injunctive relief and/or money damages, and in cases where the landlord has charged an excessive rent in violation of Section 37.9B (a), injunctive relief and/or money damages of not less than three times the amount of excess rent collected; provided, however, that any monetary award for rent overpayments resulting from a rent increase which is null and void pursuant to Section 37.3 (b)(5) shall be limited to a refund of rent overpayments made during the three-year period preceding the month of filing of the action, plus the period between the month of filing and the date of the court's order. In any case, calculation of rent overpayments and re-setting of the lawful base rent shall be based on a determination of the validity of all rent increases imposed since April 1, 1982, in accordance with Sections 37.3 (b)(5) and 37.3 (a)(2) above.

(b) Any organization with tax exempt status under 26 United States Code Section 501(c)(3) or 501(c)(4) that has a primary mission of protecting the rights of tenants in San Francisco may bring a civil action for injunctive relief and/or damages against a landlord who has wrongfully endeavored to recover, or has recovered, possession of a rental unit in violation of Section 37.9 (a)(8), or who has collected excess rent in violation of Section 37.9B (a). Such action shall be filed within three years after an affected tenant knew, or through the exercise of reasonable diligence should have known, of the facts constituting the violation. However, before bringing any action under this Section 37.11A (b), the organization shall first provide 30 days’ written notice of its intent to initiate civil proceedings by serving a draft complaint on the City Attorney’s Office and on any known address(es) of the affected tenant(s), and may bring the action under this Section 37.11A (b) only if neither the City Attorney’s Office nor the tenant(s) have initiated civil proceedings by the end of the 30 day period. Any monetary award for rent overpayments shall be for two times any excess amounts of rent charged, as well as any other sums reasonably expended to investigate and prosecute the claim, and shall be limited to the three-year period preceding the month of filing of the action, plus the period between the month of filing and the date of the court’s order.

(c) The prevailing party in any civil action brought under this Section 37.11A shall be entitled to recover reasonable attorneys’ fees and costs. The remedy available under this Section 37.11A shall be in addition to any other existing remedies which may be available.