Federal Tax - Practice. Laliberté v. Canada
In Laliberté v. Canada (Fed CA, 2020) the Federal Court of Appeal cited authoritative law on the issue of shifting onus in tax cases:
 As noted, the appellant submits that it is axiomatic in cases before the Tax Court that the onus shifts to the Crown to prove the facts sufficient to uphold the assessment where a taxpayer succeeds in establishing that the factual assumptions set out in the Minister’s reply and upon which the Minister assessed are wrong. The case law describes such circumstance as one where the taxpayer "“demolishes”" the Minister’s assumptions. The appellant relies in particular on the following passage from Hickman Motors Ltd. v. Canada, 1997 CanLII 357 (SCC),  2 S.C.R. 336, 213 N.R. 81 at paras. 92-94 (S.C.C), where Justice L’Heureux-Dubé said as follows regarding the onus in income tax cases:
92. It is trite law that in taxation the standard of proof is the civil balance of probabilities: Dobieco Ltd. v. Minister of National Revenue, 1965 CanLII 81 (SCC),  S.C.R. 95, and that within balance of probabilities, there can be varying degrees of proof required in order to discharge the onus, depending on the subject matter: Continental Insurance Co. v. Dalton Cartage Co., 1982 CanLII 13 (SCC),  1 S.C.R. 164; Pallan v. M.N.R., 90 D.T.C. 1102 (T.C.C.), at p. 1106. The Minister, in making assessments, proceeds on assumptions (Bayridge Estates Ltd. v. M.N.R., 59 D.T.C. 1098 (Ex. Ct.), at p. 1101) and the initial onus is on the taxpayer to “demolish” the Minister’s assumptions in the assessment (Johnston v. Minister of National Revenue, 1948 CanLII 1 (SCC),  S.C.R. 486; Kennedy v. M.N.R., 73 D.T.C. 5359 (F.C.A.), at p. 5361). The initial burden is only to “demolish” the exact assumptions made by the Minister but no more: First Fund Genesis Corp. v. The Queen, 90 D.T.C. 6337 (F.C.T.D.), at p. 6340.
93. This initial onus of “demolishing” the Minister’s exact assumptions is met where the appellant makes out at least a prima facie case: Kamin v. M.N.R., 93 D.T.C. 62 (T.C.C.); Goodwin v. M.N.R., 82 D.T.C. 1679 (T.R.B.). In the case at bar, the appellant adduced evidence which met not only a prima facie standard, but also, in my view, even a higher one. In my view, the appellant “demolished” the following assumptions as follows: (a) the assumption of “two businesses”, by adducing clear evidence of only one business; (b) the assumption of “no income”, by adducing clear evidence of income. The law is settled that unchallenged and uncontradicted evidence “demolishes” the Minister’s assumptions: see for example MacIsaac v. M.N.R., 74 D.T.C. 6380 (F.C.A.), at p. 6381; Zink v. M.N.R., 87 D.T.C. 652 (T.C.C.). As stated above, all of the appellant’s evidence in the case at bar remained unchallenged and uncontradicted. Accordingly, in my view, the assumptions of “two businesses” and “no income” have been “demolished” by the appellant.
94. Where the Minister’s assumptions have been “demolished” by the appellant, “the onus . . . shifts to the Minister to rebut the prima facie case” made out by the appellant and to prove the assumptions: Magilb Development Corp. v. The Queen, 87 D.T.C. 5012 (F.C.T.D.), at p. 5018. […]
[Emphasis in original.]