Cheapest train ticket from Paris to Barcelona?

I'm trying to book a special treat for my girlfriend and I have decided to book train tickets from Paris to Barcelona on the overnight train. We're leaving on June 25th, and are planning on taking the night train.

So, I've looked around a bit, and I notice that the French fare at http://www.voyages-sncf.com is cheaper than the trains on the UK sites - the best fare I've found is for 248 Euro, which isn't so bad (that price is for the First Class Double without Shower (it doesn't look like there are any single beds).

So, are there any cheaper sites where I could find this fare? We are both students, but we are 26 and 27 years old, so I think we're ineligible for the cheaper fares, if there are any. Might there be a Spanish site to get it cheaper, or a special student rate hiding somewhere? Any help would be appreciated...Thanks!

Have you thought of flying? I managed to get a Ryanair connection from Madrid into Paris (Beauvais) for 0.01 Euros. Might be cheaper. Not as romantic. :)