An approved ETIAS for Canadian citizens allows the holder to visit any and all of the countries that have signed the Schengen Agreement for passport-free travel.
This includes the 3 microstates of Monaco, San Marino, and Vatican City. These microstates maintain open or semi-open borders with other Schengen countries.
Citizens of these countries are able to travel within the Schengen borders using only a valid national ID card and are not subject to other border control measures.
However, Canadians need an approved ETIAS visa waiver to travel between Schengen member states.
Additionally, an ETIAS authorization will be required for Canadians who wish to travel to countries that are pending members of Schengen but have not fully met the aquis to be fully incorporated into the Area.
These are Croatia, Bulgaria, the Republic of Cyprus, and Romania.
Below you can find a list of countries for which an ETIAS for Canadians is required, as well as an interactive map.