SNCF strike in June 2014

I haven't been able to find a definitive answer but there is an official guide about the rules during the strike. It seems possible to get a refund even if the ticket would otherwise be non-refundable:

Tous les billets, quels que soient les tarifs, y compris "non échangeables / non remboursables" tels que Prem's seront remboursés sans frais si vous en faites la demande au guichet et ce depuis le mercredi 4 juin 2014.

It does not sound contingent on your specific train being cancelled. At the beginning of the strike, it was possible to do it well in advance but an additional complication is that workers now decide each day if they want to go on so I don't know if the SNCF already offers refunds for Sunday. It's worth a try in any case but if you buy your plane ticket before you can make sure, you might very well end up with a non-refundable TGV ticket.

As @Gagravarr said, you can take any tgv the day of the strike.

But unlike what he said, you may be able to cancel your ticket and get a refund.

If the fare is "Prem's" or iDTGV, then you cannot get a refund unless there is actually a strike, but you might not know before Saturday night.

If the fare is "Loisirs", "Loisirs Jeune" or bought with any discount card (Jeune, Senior, weekend), "TGV Pro" and I might forget some, then you can get a full refund if you cancel your ticket at least the day before. If you have an e-ticket then you can cancel it online, if it is a paper ticket then go to the station.

If you are not sure of the conditions of your ticket, read your reservation, it should be written.

Short answer - no, you can't get a refund on a non-refundable ticket until your train is announced as cancelled, but it probably doesn't matter...

If your train is cancelled, you'll be able to get a full refund of the ticket cost of the cancelled train, no matter what the conditions normally on it. You can do that at the station (expect epic queues), or via a few options detailed on Info Lignes.

However, on most routes, there are still trains running, just not the full number. Checking for tomorrow morning, I'm seeing most but not all Paris to Aix-en-Provence-TGV trains running. If your train is cancelled, you'll be able to travel on any other service over that route on the same day. Won't be at the same time, may well involve a delay, and you might have to stand if you're unlucky (no promise of a seat if your train was cancelled), but you'll still be able to travel.

(Some routes everything or almost everything is cancelled, in which case you'd be out of luck beyond getting the refund, but Paris to Aix-en-Provence isn't currently in that category. If you have a refundable ticket, you could get a refund for any reason, but I'm assuming you don't if you have to ask here!)