Since the usual limit for booking on the SNCF site is 90 days in advance, I don't know why 2 July comes up on the site. But you might as well take advantage of it. It used to be simple to book in English, but since SNCF revised its site it is now quite complicated. Here's how to do it:
Go here: http://tinyurl.com/2shmfn. You will get a page with the heading "Document non trouvé." Click on the British flag icon. Wait a few moments for the page to re-set even though it will appear as if nothing changes and it will stay in French. Click on the "consulter le plan du site" link. Under the Train heading click on the "Reservation billet train" link. You'll get a booking page whose heading is in French, but the rest will be in English. Since you'll be picking up your tickets in the French section of the Geneva train station, leave France as the default country. Enter Geneve as the departure point and Paris as your arrival point. Click on "Search now" in the lower right-hand corner.
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