What will happen if I enter Canada as a citizen of Canada with a?
As a Canadian citizen, you are no longer allowed to apply for an eTA. However, if for some reason you do not have your Canadian passport, you can apply for a special authorisation that will allow you to enter on your French passport. This happened to me on my Polish passport when my Canadian passport was expired and I couldnt get a new one in time. The information for applying for a special authorisation is here: Dual Canadian citizens need a valid Canadian passport. It only took about an hour for me to get the email approval, but you have to do it within 10 days of your flight date, and it is only valid for entry for 4 days (though you can stay as long as you like).