I think those are Nervar cranks - those and the comparable cottered steel Stronglights turn up on the big auction site all day long, and are usually pretty cheap. OR, find an older LBS that hasn't thrown stuff out in a while. Many of those cranks languish because there has been an automatic "Eeek! It's a cottered crank!" reaction to them since the early 70s when cheap cotterless alloy cranks became available.

Verktyg hasn't chimed in yet, but a search for his posts would be helpful. Also, consider going to gitaneusa.com :: View Forum - Vintage Gitane and trawling for information there. There is a LOT of Gitane specific information available there.

If you are not in a huge hurry, and the price is right, I would say grab it. I personally think Gitanes are some of the best riding bikes ever made, and after kicking myself for letting several of them go through the years, a '71 Tour de France is currently in my "keep forever" stable as a fixed-gear road bike. If I ran up on a Grand Sport Deluxe in my size (60 cm) at a good price at a time when I had disposable income, I would snap it up.

The issues you would encounter (potentially) are -

- The French threaded BB which should NOT be a problem, really. It just means your LBS will probably not be able to help you, but you've already seen other options. Or just service it yourself if you decide to stick with the stock cranks - there are directions out there for a homebrew cotter press, and take your time and re use the originals and you'll be fine.

- The derailleurs. Frankly, the stock Delrin Simplex Prestige was a neat idea that doesn't last well. A previous owner did you a favor by fitting a SunTour rear derailleur, and were it my bike I would quietly seek out a set of downtube SunTour ratcheting shift levers and maybe a SunTour front derailleur and call it a day. They will work so much better, and back when, LOTS of riders did just that. I rode all over the Blue Ridge Parkway in the mid-70s on a bike with a Simplex front derailleur and SunTour rear. ANY derailleurs will work.

- The headset. Again, there are a zillion workarounds, but first just clean and relube the stock one. It is amazing how durable these things are, and in in all likelihood a good scrubbing and fresh ball bearings and grease will restore it to new. It is highly likely that this is a low-mileage bike anyway, and you're mostly cleaning and relubing something that saw little use.

- The wheels. In all likelihood, the hubs are stock Normandy Sports. The overwhelming majority of these will take a standard threaded freewheel, because Mel Pinto, who brought them into the country during those years, spec'ed them out that way. If it has stock steel rims, take your time and find some alloy rims and the appropriate stainless steel spokes and rebuild them - or just be on the lookout for a nicer set of vintage wheels and pop them on. If you indeed have Normandy hubs, clean them out and repack the bearings. I was amazed at how smooth the last set I worked with was, fitted to a similar Motobecane that spent most of the last 40 years in a muddy crawlspace in South Carolina.