CRA notes that a capital gain’s geographic source for Canadian FTC purposes was re-sourced to Australia under the Treaty-source rule

A Canadian-resident individual is subject to Australian gains tax on the gain from selling the shares of a U.K. holding company holding an Australian real estate corporation. Under the Canadian domestic situs rules, the gain would have a U.K. source so that there would be no Canadian foreign tax credit for the Australian tax – but this is remedied by Art. 22(2) of the Canada-Australia Treaty (broadly similar, for example, to Art. 24(3) and 21(3) of the U.S. and U.K Treaties, respectively), which provides that income or gains of a Canadian resident which are taxed in Australia in accordance with Art. 13 of the Treaty are relevantly deemed to be sourced in Australia.

Neal Armstrong. Summary of 26 November 2020 STEP Roundtable, Q.4 under Treaties – Income Tax Conventions – Art. 24.