Bike looks like a 1977 "Gitane" 600 Léger....
From 1974 through 1977 Gitanes were imported and distributed by Gitane Pacific located in Southern California. When they took over from Mel Pinto Imports, Gitane Pacific cut the number of French made Gitane models by half including most of the upper tier bikes.
Gitane Pacific imported a number of Asian made models from both Japan and Taiwan. These had decals and head badges that were different from the "real" Gitanes.
My guess at the value is $150-$250 USD. It could be worth a little more to the right person because of the large frame size. There's a section in the forum where you can get estimates on the value of C&R stuff but they frown on fishing for selling purposes.
verktyg
Chas.