10-15 min in advance is usually a good idea for big stations like Paris-Est. More is not necessary since platforms are announced last-minute resulting in everyone rushing at the same time...

Thank you but a follow up question.  Is there time that should be allowed for security checks, luggage screening, etc.?  Also….we are Canadian….is there passport control that also adds time?

Thank you in advance

There is no security check,  luggage screening or passport control within the Schengen/EU area.

Only if  you would travel to/from UK there are checks.