As a general rule, international students in Canada are required to pay tax on any income that they earn while in the country. This includes scholarship income, as well as income from employment, business, or other sources.
The amount of tax that you are required to pay will depend on the amount of your income, your tax rate, and any deductions or credits that you are eligible for. In Canada, international students are generally required to file a tax return if they have income from any source in Canada, even if the income is less than CAD 10,000.
If you received a scholarship of CAD 1,500 and you were required to pay CAD 300 in tax, this likely means that you had other income in addition to the scholarship income, and that the tax withheld from your scholarship was not sufficient to cover your total tax liability. In this case, you will need to file a tax return to report your total income and pay any additional tax that you owe.
If you are unsure about your tax obligations or if you have questions about how to file a tax return in Canada, I recommend seeking the advice of a qualified tax professional or consulting with the Canada Revenue Agency (CRA) for more information. The CRA has a number of resources available to help international students understand their tax obligations and to assist them with filing their tax returns.