US Code Chapter 45 - Fair Housing -Subchapter I, Section 3605

§ 3605. Discrimination in residential real estate-related transactions

(a) In general
It shall be unlawful for any person or other entity whose business includes engaging in residential real estate-related transactions to discriminate against any person in making available such a transaction, or in the terms or conditions of such a transaction, because of race, color, religion, sex, handicap, familial status, or national origin.
(b) "Residential real estate-related transaction" defined
As used in this section, the term "residential real estate-related transaction" means any of the following:

(1) The making or purchasing of loans or providing other financial assistance -

(A) for purchasing, constructing, improving, repairing, or maintaining a dwelling; or

(B) secured by residential real estate.

(2) The selling, brokering, or appraising of residential real property.

(c) Appraisal exemption
Nothing in this subchapter prohibits a person engaged in the business of furnishing appraisals of real property to take into consideration factors other than race, color, religion, national origin, sex, handicap, or familial status.