Upvote:1
Let me introduce you to Skyscanner.
Skyscanner searches a vast array of airlines and air travel websites, to obtain the lowest fares publicly available.
For your proposed one-way trip leaving Toronto on July 1 and going to Paris, it comes up with $585 on Condor ($713 CAD at today's exchange rate) as the cheapest flight, YYZ-FRA-CDG. If you leave late the previous night instead, you can get a nonstop flight for $590 $629 (you were too slow and missed it).
I think you will find it quite difficult to do better than that.