Subletting a rented property, commercial or residential, is not illegal in California, as far as the law is concerned. In California, most leases state that the landlord's consent to a sublease is not to be unreasonably withheld.Subletting your office space or commercial property? Easily customize your own Commercial Sublease Agreement. First, typically your landlord must give consent to either an assignment of the lease or a sublease. Generally speaking, there are two aspects here. A commercial sublease agreement (CLA) is a contract that clarifies the applicable conditions if a tenant subleases its commercial space.