It shall be considered a violation of Title I of the Act to discriminate against any individual on the basis of outward appearance for purposes of recruitment, hiring, or promotion. However, an employer may prescribe standards of appearance or dress for personnel which serve a reasonable business purpose; for example, to identify its employees to the public by means of a distinctive uniform, or to maintain a neat and clean appearance.
Characteristics such as hair or dress style may be symbolic of race, national origin, or religion, and action to limit or prevent their use shall constitute a form of discrimination, unless the employer can show a reasonable business purpose.
D.C. Mun. Regs. tit. 4, r. 4-513