A California sublease agreement is a written arrangement that involves a residential tenant leasing their rental property to a subtenant. California law requires tenants to seek explicit, written permission from their landlords to sublet if it is not already allowed in the lease.Should you allow tenants to sublease? This article covers how subleasing works and what the risks are for landlords. Create your California sublease agreement here. Rent your unit to a subtenant and download our free template. In California, most leases state that the landlord's consent to a sublease is not to be unreasonably withheld.