Section 821 - Enforcement and penalties1. Whenever there shall be a violation of this article, an application may be made by the attorney general in the name of the people of the state of New York to a court or justice having jurisdiction by a special proceeding to issue an injunction to enjoin and restrain the continuance of such violations; and if it shall appear to the satisfaction of the court or justice that the defendant has, in fact, violated this article, an injunction may be issued by such court or justice enjoining and restraining any further violation, without requiring proof that any person has, in fact, been injured or damaged thereby. In any such proceeding, the court may make allowances to the attorney general as provided in paragraph six of subdivision (a) of section eighty-three hundred three of the civil practice law and rules, and direct restitution. Whenever the court shall determine that a violation of this article has occurred the court may impose a civil penalty of not more than five hundred dollars for each violation. For the purposes of this section each group of identical items shall constitute a single violation. In connection with any such proposed application, the attorney general is authorized to take proof and make a determination of the relevant facts and to issue subpoenas in accordance with the civil practice law and rules.2. Before any violation of this article is sought to be enjoined, the attorney general shall be required to give the person against whom such proceeding is contemplated notice by certified mail and an opportunity to show in writing within five business days after receipt of notice why proceedings should not be instituted against him, unless the attorney general shall find, in any case in which he seeks preliminary relief, that to give such notice and opportunity is not in the public interest.3. In any such action it shall be a complete defense that the act or practice is, or if in interstate commerce would be, subject to and complies with the rules and regulations of, and the statutes administered by, the federal food and drug administration or any official department, division, commission or agency of the United States as such rules, regulations or statutes are interpreted by the federal food and drug administration or such department, division, commission or agency or the federal courts.