There is a 4K AF points difference if I'm leaving from CDG rather than ZYR.
Some representatives told me that I can just call in the same day if "I can't make it to the train..." and still keep the flight, and some told me that I will lose the whole flight for the no-show. Of course, I still have the option to modify the itinerary the same day for a $50 fee.
Any experience with that? (I know that they do a small check-in before the train)
On saver award economy it's only 500 points difference.