California Code, Code of Civil Procedure - CCP § 116.430

(a) If the plaintiff operates or does business under a fictitious business name and the claim relates to that business, the claim shall be accompanied by the filing of a declaration stating that the plaintiff has complied with the fictitious business name laws by executing, filing, and publishing a fictitious business name statement as required.

(b) A small claims action filed by a person who has not complied with the applicable fictitious business name laws by executing, filing, and publishing a fictitious business name statement as required shall be dismissed without prejudice.

(c) For purposes of this section, “fictitious business name” means the term as defined in Section 17900 of the Business and Professions Code, and “fictitious business name statement” means the statement described in Section 17913 of the Business and Professions Code.