Chouteghi30 What discount do you have on your SwissPass? Half fare? GA?
For the TGV Lyria, it depends of the day and time of your trip, the date of the purchase, the selected service, if the ticket is flexible or not.
You can indicate the travelcard you have and see if any discount is available. If you travel often with the TGV Lyria, you should also buy a discount card valid in France (for example the Carte Avantage).