unfortunately, Gitane serial#'s don't seem to mean much. That downtube decal was still used until '73, but the headtube decal, at least for US models, puts it into the 60's. You didn't say where you were located.

I'm going to guess 1966, but am easily willing to be overruled.

There have been some parts changed out. The rear wheel and rear derailleur at a minimum.