How do I actually claim treaty relief between India and Canada?
In two places, and the order matters. Before the money moves, you give the Indian payer evidence that you are resident in Canada, so the deduction is made at the treaty rate rather than the domestic one. After the year ends, you claim what the treaty gives you on the return in each country, with the credit for tax paid on one side supported by the documents from the other. Miss the first step and the relief still exists, but it turns into a refund claim that takes months instead of a smaller deduction at the time of payment.
Do I need a residence certificate to get the treaty rate?
The payer has to be satisfied that you are resident in the other country before applying anything other than the domestic rate, and a certificate from the tax authority where you live is the ordinary way to show it. Obtain it before payments start rather than in response to a deduction, because the payer cannot undo what has already been deposited. Keep a copy with that year's papers. If the relief is ever questioned, the certificate and the payment record are the two documents the whole claim rests on.
Can I recover tax deducted at the domestic rate instead of the treaty rate?
Yes, but through India rather than through Canada. The excess was collected by the Indian system, so the Indian return is where it is claimed back; asking Canada to give credit for more than the treaty allowed simply moves the problem across the border. That distinction catches people out regularly, because the loss appears on the Canadian return while the remedy sits in the other country. File in India for the year, claim the difference there, and treat the Canadian credit as limited to what the treaty permitted the other side to take.
Can I claim credit in Canada for the tax I paid in India?
Generally yes, up to the amount the treaty allowed India to take on that income. The difficulty is rarely the principle and almost always the arithmetic, because the Indian year runs April to March while the Canadian return covers the calendar year. The Indian tax has to be recut onto the Canadian year before it can be claimed, and the supporting documents have to show that convincingly. Deduction certificates and the Indian return itself are what carry it. An annual Indian figure dropped whole onto a Canadian return will not stand up.
Does the treaty apply automatically or do I have to claim it?
You claim it. Neither system applies the treaty to your situation on its own, and the default is that each country taxes under its own law, with India collecting at source before any relief has been considered. The claim has to be made in the right place at the right time: with the payer, so the deduction is right, and on each return, so the credit is right. Treat it as a document exercise running alongside the money, not as something to be sorted out once the returns are being prepared.
Which country taxes my income first under the India Canada treaty?
That depends on the class of income, and it is the first thing to settle because everything else follows from it. The treaty deals with each class in its own article, and the answer for rent from a flat is not the answer for deposit interest, for a pension, or for employment carried out in one country and paid from the other. Identify the class, read the article that governs it, then work out who taxes first and who gives the credit. Doing those in the wrong order is how one income ends up fully taxed twice.
Do dual citizens pay taxes in both countries?
Both countries can have a claim, but paying double taxes on the same dollar is the exception rather than the rule. The United States taxes its citizens wherever they live; Canada, India and most others tax on residence. So a dual citizen living in one of them often files in both — a resident return in one, a citizen return in the other — while the credit and exclusion rules mean the total is usually close to the higher of the two, not the sum. Filing twice is not paying twice. See two returns as a dual citizen.
How do you avoid double taxation?
You claim relief once, in the right country, in the right order. Usually the source country taxes first, the residence country then gives a credit for that tax against its own charge on the same income, and a treaty caps the source-country rate. Getting the order wrong is what produces a double charge you then have to unwind. The mechanism differs by income type, which is why we map the whole position before filing either return. See how to avoid double taxation.