If your flight from Canada originates from YYZ or YUL then consider 1.5 hr delay to be on the safe side.
If you arrive at CDG 2A from Canada then usually you are cleared quickly in less than 1 hr ...and then you have 15min walk to CDG TGV T2 train departure station.
Booking SNCF trains is done best through French web site SNCF
before paying online for your SNCF ticket double check departure date and time because sometimes due to booking from a different TZ date shown scrolls back/forth by 1 day.