Do Cdn residents who sold shares traded on foreign exchanges (NYSE) and are reporting it on their Cdn income tax return pay withholding tax or capital gains tax?

There is even a special form called a Form T1135 – Foreign Income Verification Statement that is meant for reporting foreign assets and income to the CRA. It is used to report “specified foreign property” if your cost for certain foreign assets exceeded $100,000 Canadian (based on the exchange rates at the time of purchase) at any time during the year.

Most “investment assets” like U.S. stocks would be considered specified foreign property, whereas personal-use real estate like a vacation property that is not rented out and only used personally would be excluded.

The treaty requires 15% tax withholding on dividends and 10% tax withholding on interest. So if you own a U.S. stock, as a Canadian resident, there will be 15% withholding tax on any dividends earned.

I have sold US stocks, with a capital gain less that 100 000$.  So I understand I cannot use form T1135.  Where do I enter the income from that sale ?  Thanks.

You can enter your foreign capital gain on the Foreign Slip in TurboTax. The purpose of Form T1135 is to identify foreign property. The $100,000 threshold means that as a Canadian resident you do not need to comply with the reporting requirements of Form T1135 if you are below the $100,000 threshold, however, you are not exempt from paying taxes.