The forfeitures provided for in this chapter shall be payable into the Treasury of the United States, and shall be recoverable, except as otherwise provided with respect to a forfeiture penalty determined under section 503(b)(3) of this title, in a civil suit in the name of the United States brought in the district where the person or carrier has its principal operating office or in any district through which the line or system of the carrier runs: Provided, That any suit for the recovery of a forfeiture imposed pursuant to the provisions of this chapter shall be a trial de novo: Provided further, That in the case of forfeiture by a ship, said forfeiture may also be recoverable by way of libel in any district in which such ship shall arrive or depart. Such forfeitures shall be in addition to any other general or specific penalties provided in this chapter. It shall be the duty of the various United States attorneys, under the direction of the Attorney General of the United States, to prosecute for the recovery of forfeitures under this chapter. The costs and expenses of such prosecutions shall be paid from the appropriation for the expenses of the courts of the United States.
The forfeitures imposed by subchapter II, parts II and III of subchapter III, and sections 503(b) and 507 of this title shall be subject to remission or mitigation by the Commission under such regulations and methods of ascertaining the facts as may seem to it advisable, and, if suit has been instituted, the Attorney General, upon request of the Commission, shall direct the discontinuance of any prosecution to recover such forfeitures: Provided, however, That no forfeiture shall be remitted or mitigated after determination by a court of competent jurisdiction.
In any case where the Commission issues a notice of apparent liability looking toward the imposition of a forfeiture under this chapter, that fact shall not be used, in any other proceeding before the Commission, to the prejudice of the person to whom such notice was issued, unless (i) the forfeiture has been paid, or (ii) a court of competent jurisdiction has ordered payment of such forfeiture, and such order has become final.