(765 ILCS 720/1) (from Ch. 80, par. 71)

Sec. 1. It is declared to be against the public policy of the State for a landlord to terminate or refuse to renew a lease or tenancy of property used as a residence on the ground that the tenant has complained to any governmental authority of a bona fide violation of any applicable building code, health ordinance, or similar regulation. Any provision in any lease, or any agreement or understanding, purporting to permit the landlord to terminate or refuse to renew a lease or tenancy for such reason is void.

(Source: Laws 1963, p. 1508.)