As other people already said, you (most probably) have to declare your income in the country you are living in. It doesn’t matter if you are paid in CAD, or if you’re an entrepreneur in France already.
The authorities usually check where your main place of residence is located. That’s where you (usually) have to pay taxes.
As @Bojack already said, for most countries there are bilateral treaties to avoid being double taxed. I know the double tax treaty between Germany and Switzerland pretty well, and even though the standard cases are usually clear, for special cases you have to seek professional advice.
One thing I noticed: you really have to make sure you get professional advice from someone who is specialized in international tax laws. In German, that would be a tax adviser who has the qualification “Fachberater für internationales Steuerrecht” = expert adviser for international tax law
Most of the Swiss tax advisers (Treuhänder) I met so far don’t really know about international treaties.
Another thing to mention: since you are working completely from home for a Canadian company, this could lead to tax problems for the company as well. Unless they hire you as a freelancer. Also, if you’re working remote: in Germany, you are not allowed to work more than 25% of your work time from home if you are a border-crosser. If you do, you will have to pay all taxes/health insurance etc in Germany.
I think you don’t need to register and can just add it as additional income in your tax declaration. But I’m just an anonymous guy in an internet forum, so don’t take my word for granted
Search for someone who is specialized in international tax laws. Best would be someone who is targeting US/CAD expats, from my point of view.