I can't claim to be an expert on Gitane, but every one I have seen from that era has had severely faded paint. The color may be off, but the coating seems intact. The decals still look pretty good, so I would be hesitant to repaint unless you really don't like the fade. If you decide to repaint, just lightly scuff the original paint without removing it. That way the new paint will stick while retaining the hardness of the original paint.