Cal. Sts. & Hy. Code § 5613
The postal card shall contain a notice to repair the sidewalk so out of repair, and the superintendent of streets shall, immediately upon the mailing of the notice, cause a copy thereof printed on a card of not less than 8 inches by 10 inches in size, to be posted in a conspicuous place on the property. In lieu of posting a copy of the mailed notice on the property as provided in this section, the superintendent of streets may, not less than seven days nor more than 10 days after the mailing of the first postal card notice, mail an additional postal card, postage prepaid, marked "Second Notice," to the person to whom the first postal card notice was addressed. The second notice shall otherwise contain the material required by this article, but shall not extend the time for commencing repairs specified in Section 5614.
Ca. Sts. and High. Code § 5613