Belvidere — Ch. 62 Human Relations § 62-33

It is a civil rights violation for an owner or any other person engaging in a real estate transaction, or for a real estate broker or salesman, because of unlawful discrimination or familial status, to: (1)
Transaction. Refuse to engage in a real estate transaction with a person or to discriminate in making available such a transaction.
(2) Terms. Alter the terms, conditions or privileges of a real estate transaction or in the furnishing of facilities or services in connection therewith.
(3) Offer. Refuse to receive or to fail to transmit a bona fide offer to engage in a real estate transaction from a person.
(4) Negotiation. Refuse to negotiate for a real estate transaction with a person.
(5) Representations. Represent to a person that real property is not available for inspection, sale, rental or lease when in fact it is so available, or to fail to bring a property listing to his attention, or to refuse to permit him to inspect real property.
(6) Publication of intent. Print, circulate, post, mail, publish or cause to be so published a written or oral statement, advertisement or sign, or to use a form of application for a real estate transaction, or to make a record of inquiry in connection with a prospective real estate transaction, which expresses any limitation founded upon, or indicates, directly or indirectly, an intent to engage in unlawful discrimination.
(7) Listings. Offer, solicit, accept, use or retain a listing of real property with knowledge that unlawful discrimination or discrimination on the basis of familial status in a real estate transaction is intended.
State Law reference-- Similar provisions, 775 ILCS 5/3-102.