CRA has required PayPal to disclose sales and other transaction records for Business Account Holders from January 1, 2014 to November 10, 2017. It is expected CRA will review records for unreported sales. For more details, see https://www.paypal.com/ca/smarthelp/article/cra-information-request-faq3755
On an unrelated note, you can now also pay your taxes via PayPal. For more information, see https://www.canada.ca/en/revenue-agency/services/about-canada-revenue-agency-cra/pay-credit-card.html
In the summer of 2016, CRA commenced a project to examine taxpayers holding expensive properties in Vancouver where only low amounts of income were reported. The goal of the project was to identify unreported worldwide income, property “flipping”, underreporting of capital gains on sales, and underreporting GST on sales of new homes. CRA has reported that they recovered more than $30 million as a result of this project.
For more information about this project and its result, see: http://www.cra-arc.gc.ca/gncy/cmplnc/rlstt/menu-eng.html.