California Code, Government Code - GOV § 64622

(a) A commercial linkage fee established, increased, or imposed pursuant to this article shall not exceed the reasonable cost of providing the housing necessitated by the commercial development project for which the commercial linkage fee is imposed, as determined in the regional nexus study pursuant to subdivision (b) of Section 64621, and the authority's related administrative costs.

(b) It is the intent of the Legislature in adding this section to codify existing constitutional and decisional law with respect to the imposition of development fees and monetary exactions on developments by local agencies.  This section is declaratory of existing law and shall not be construed or interpreted as creating new law or as modifying or changing existing law.