California Code, Health and Safety Code - HSC § 33501.5

In any judicial action specified in Section 33501 in which the validity of actions of the agency under Section 33334.2, 33334.3, or 33334.6 are in issue, the party initiating the judicial action or otherwise challenging the validity of those actions of the agency shall serve a copy of the complaint or answer alleging that invalidity upon the Director of Housing and Community Development within 10 days after filing that complaint or answer with the court. The court may render no judgment in the matter or provide other permanent or provisional relief to any party until proof of service of the Director of Housing and Community Development pursuant to this section has been submitted to the court. Nothing in this section shall be deemed to expand the scope of Section 33501.