Cal. Gov. Code § 9113
An amount of space proportional to the amount of space utilized by the executive branch in the existing State Capitol Building Annex described in Section 9105, or another amount of space as determined by the agreement entered into pursuant to paragraph (1) of subdivision (b) of Section 9112, within any state capitol annex constructed, or within the restored, rehabilitated, renovated, or reconstructed State Capitol Building Annex described in Section 9105, shall be under the control of the Department of General Services. All other space in the newly constructed state capitol annex or the restored, rehabilitated, renovated, or reconstructed State Capitol Building Annex shall be allocated from time to time by the Joint Rules Committee in accordance with its determination of the needs of the Legislature and the two houses thereof. The committee shall allocate to the Senate and Assembly, respectively, the space it determines to be needed by those houses and their committees and the officers, employees, and attach thereof. The space allocated to the Senate and to the Assembly pursuant to this section shall be allotted from time to time by the Senate Rules Committee and the Assembly Rules Committee, respectively.
Ca. Gov. Code § 9113