Fair Housing and Anti-Discrimination Requirements
Protected classes
The federal Fair Housing Act covers race, color, religion, sex (HUD treats sexual orientation and gender identity as within sex discrimination), national origin, familial status, and disability. The Illinois Human Rights Act adds ancestry, age, marital status, order of protection status, military status, sexual orientation including gender identity, pregnancy, and source of income for real estate transactions - meaning refusing a housing voucher is illegal statewide. Local ordinances (Chicago, Cook County, and others) add still more classes such as housing status, so always apply the strictest applicable list.
Prohibited practices
Refusing to rent, quoting different terms or deposits, steering applicants to certain buildings or floors, blockbusting (panic selling), redlining, discriminatory advertising, harassment, and retaliation are all violations. Disability analysis splits into two boxes: reasonable accommodation changes rules, policies, or services at no cost to the tenant (an assistance animal, an assigned parking space, a transfer); reasonable modification is a physical change, allowed at the tenant's expense where the lease requires it. Assistance animals are not pets, so no pet rent, pet deposit, or breed/weight limits apply. Familial status means no 'adults only' buildings and no steering families with children to the first floor.
Traps
Advertising phrases like 'perfect for young professionals,' 'no children,' or 'English speaking' are violations because they describe preferred people rather than the property. Steering can be as simple as deciding which unit to show. Two-per-bedroom occupancy is a common safe harbor, not an absolute cap.
Worked example
An applicant with a documented service dog applies to a no-pets building with a $300 pet fee. Correct handling: waive the fee, permit the animal, and do not limit it by breed or weight.