La Souveraine, Compagnie d'assurance générale v. Autorité des marchés financiers, 2013 SCC 63 deals with due diligence in regulatory law and declines to decide whether reasonable mistake of law can be a defence in regulatory matters. The Court holds:
 The due diligence defence is available if the defendant reasonably believed in a mistaken set of facts that, if true, would have rendered his or her act or omission innocent. A defendant can also avoid liability by showing that he or she took all reasonable steps to avoid the particular event (Sault Ste. Marie, at p. 1326). The defence of due diligence is based on an objective standard: it requires consideration of what a reasonable person would have done in similar circumstances.
 However, this defence will not be available if the defendant relies solely on a mistake of law to explain the commission of the offence. Under Canadian law, a mistake of law can ground a valid defence only if the mistake was an officially induced error and if the conditions laid down in R. v. Jorgensen,  4 S.C.R. 55, with respect to the application of such a defence are met. A defendant can therefore gain nothing by showing that it made a reasonable effort to know the law or that it acted in good faith in ignorance of the law, since such evidence cannot exempt it from liability.