39 U.S.C. § 1009Section
§ 1009. Personnel not to receive fees
An officer or employee of the Postal Service may not receive any fee or perquisite from a patron of the Postal Service on account of the duties performed by virtue of his appointment, except as authorized by law.
(Pub. L. 91–375, Aug. 12, 1970, 84 Stat. 733.)
