California Code, Family Code - FAM § 5252

(a) An assignment order under this article may be issued only upon an application signed under penalty of perjury by the obligee that the obligor is in default in support payments in a sum equal to the amount of support payable for one month, for any other occurrence specified by the court in the support order, or earlier by court order if requested by the local child support agency or the obligor.

(b) If the order for support does not contain a provision for an earnings assignment order for support, the application shall state that the obligee has given the obligor a written notice of the obligee's intent to seek an assignment order if there is a default in support payments and that the notice was transmitted by first-class mail, postage prepaid, or personally served at least 15 days before the date of the filing of the application.  The written notice of the intent to seek an assignment order may be given at any time, including at the time of filing a petition or complaint in which support is requested or at any time subsequent thereto.  The obligor may at any time waive the written notice required by this subdivision.

(c) In addition to any other penalty provided by law, the filing of the application with knowledge of the falsity of the declaration or notice is punishable as a contempt pursuant to Section 1209 of the Code of Civil Procedure.