I just received this notice this morning and thought I'd share it with you.
If you're planning to travel in France anytime between now and September 2, you may be interested in this sale;
oui.sncf/TGV- ticket-sale
FYI: You must book tickets before June 30th!
I didn't read the specifics, so don't know if buying discounted tickets in advance is a better deal that what is offered by this sale.
Bon Voyage!
Priscilla