After about the third week in June, there's a second flight to YUL from CDG, late afternoon. Don't know if it's daily. Presumably seasonal. In fact, I think I recall reading something about an extra flight being added on another website.
I noticed a while back that the YYZ flight flipped departure times with the YUL flight. YUL departure used to be about 1:30 and YYZ, 11:30 (non daylight savings time). I wondered how permanent the shift might be. Will it revert back next month with the summer schedule updates?
Good luck with this.