5 U.S.C. § 2904

Oath; administered without fees

An employee of an Executive agency who is authorized to administer the oath of office required by section 3331 of this title , or any other oath required by law in connection with employment in the executive branch, may not charge or receive a fee or pay for administering the oath.

( Pub. L. 89–554 , Sept. 6, 1966 , 80 Stat. 412 .)