Those rarer than a needle in a haystack bikes are always hard to attach a price to. But here are some historical ads:

Bikeville (March 22, 2012), asking $400
NOS bike, Dec 11, 2011, Oakland, OR, Asking $880
E-Bay, Buy-it-now, Nov 12, 2013, $269+$55.09 (had been listed as auction a few times for $199 and hadn't been sold).
E-Bay, Oct 12, 2016, $299 + $150. Unsold

The current Craigslist ad in Seattle
1974 Gitane Super Corsa - $1049 (Seattle)

This is a tough one. Anything is worth two things... what a buyer is willing to pay, and of course having a potential buyer actually FIND it.

Based on previous sales history, I'd probably put the value at somewhere between about $200 and $400. That bike looks nice, but it does have some deep rust through the chrome on the bottom bracket.