In Beaudry v. The Queen, my colleague Tardif J. describes the Crown’s burden in the context of a subsection 160(1) assessment as follows:
 There is an exception, and Archambault J. dealt with that exception inGestion Yvan Drouin:
Since it is the Minister who takes measures against a third party to recover the tax owed to him by the tax debtor, it seems entirely reasonable to me that it should be incumbent on the Minister to provide prima facie evidence of the existence of the tax liability. To do this, the Minister usually has in his possession the tax debtor's tax return and, if he has carried out an audit, he may have copies of the source documents or other relevant documents supporting his assessment. He is therefore the one who is in the best position to establish the quantum of the tax liability. I thus conclude that the onus of providing prima facie evidence of the tax liability where an assessment has been made under subsection 160(1) of the Act generally falls on the Minister.
… As soon as the Minister has proved prima facie the existence of the tax liability, the onus is on the transferee to provide evidence to the contrary.
 I agree with this observation.
 Ms. Rueger, however, provided no explanation as to why Mr. Ellis was assessed gross negligence penalties under subsection 163(1) [s/b 163(2)] of the Act. In view of the failure to establish the circumstances that justify the imposition of a penalty, the penalties must be eliminated from the Appellant’s assessment.
Also noteworthy here, the appellant had not raised this issue of proof of the transferor's tax debts in her notice of appeal but the Court allowed the argument anyway:
 In her written representations, the Respondent argues that the Appellant did not dispute the Transferor’s tax debt in her amended notice of appeal. I observe that the Appellant was not represented by counsel when she prepared her amended notice of appeal. I do not believe that the Respondent suffered prejudice from the aforementioned shortcoming. The Appellant had arranged to call Ms. Rueger as a witness. Her testimony was required to explain the significant changes to Mr. Ellis’ tax liability brought about by the numerous reassessments that were issued against him, since the Appellant was assessed under subsection 160(1). In that context, it was clear that Mr. Ellis’ tax liability had to be established at trial.
Ellis v. The Queen 2015 TCC 285 (Hogan)