Cal. Fam. Code § 3667
Upon the subsequent filing of a motion for modification or termination of the support order by the requesting party, if the court finds that the income and expense declaration submitted by the responding party pursuant to this article was incomplete, inaccurate, or missing the prior year's federal and state personal income tax returns, or that the declaration was not submitted in good faith, the court may order sanctions against the responding party in the form of payment of all costs of the motion, including the filing fee and the costs of the depositions and subpoenas necessary to be utilized in order to obtain complete and accurate information. This section is applicable regardless of whether a party has utilized subdivision (b) of Section 3664.
Ca. Fam. Code § 3667