Cal. Civ. Proc. Code § 1166
(a) The complaint shall:
(d)
(1) In an action regarding residential property, the plaintiff shall attach to the complaint the following:
(B) A copy of any written lease or rental agreement regarding the premises. Any addenda or attachments to the lease or written agreement that form the basis of the complaint shall also be attached. The documents required by this subparagraph are not required to be attached if the complaint alleges any of the following: