Subchapter D - Miscellaneous Penalty and Forfeiture Provisions

26 USC 7341 - Penalty for sales to evade tax

(a) Nonenforceability of contract 
Whenever any person who is liable to pay any tax imposed by this title upon, for, or in respect of, any property sells or causes or allows the same to be sold before such tax is paid, with intent to avoid such tax, or in fraud of the internal revenue laws, any debt contracted in such sale, and any security given therefor, unless the same shall have been bona fide transferred to an innocent holder, shall be void, and the collection thereof shall not be enforced in any court.
(b) Forfeiture of sum paid on contract 
If such property has been paid for, in whole or in part, the sum so paid shall be deemed forfeited.
(c) Moiety 
Any person who shall sue for the sum so paid (in an action of debt) shall recover from the seller the amount so paid, one-half to his own use and the other half to the use of the United States.

26 USC 7342 - Penalty for refusal to permit entry or examination

Any owner of any building or place, or person having the agency or superintendence of the same, who refuses to admit any officer or employee of the Treasury Department acting under the authority of section 7606 (relating to entry of premises for examination of taxable articles) or refuses to permit him to examine such article or articles, shall, for every such refusal, forfeit $500.

26 USC 7343 - Definition of term person

The term person as used in this chapter includes an officer or employee of a corporation, or a member or employee of a partnership, who as such officer, employee, or member is under a duty to perform the act in respect of which the violation occurs.

26 USC 7344 - Extended application of penalties relating to officers of the Treasury Department

All provisions of law imposing fines, penalties, or other punishment for offenses committed by an internal revenue officer or other officer of the Department of the Treasury, or under any agency or office thereof, shall apply to all persons whomsoever, employed, appointed, or acting under the authority of any internal revenue law, or any revenue provision of any law of the United States, when such persons are designated or acting as officers or employees in connection with such law, or are persons having the custody or disposition of any public money.