To set up a new business account to file your Business Property Statement, please call (925) 313-7600 for more information. Subletting a rented property, commercial or residential, is not illegal in California, as far as the law is concerned.Blue Line Property Management's experienced East Bay property managers will help you navigate the real estate and rental market in Contra Costa County.. This document outlines the terms under which the sublessee will rent the property from the sublessor, defining the dynamics of this unique legal relationship. Find Walnut Creek, CA commercial real estate for lease and sale on PropertyShark. Discover 143 properties including offices, retail, and industrial spaces. Official Forms for Viewing and Downloading. A sublease, or sublet, occurs when a tenant assigns part or all of their lease to a new tenant. In general, most commercial leases permit subletting. Interested in retail property investment?