Hi, great to read these posts. I've lived in France for 32 years but only recently started bike touring here. Last summer I did a 10 day jaunt from Atlantic coast downwards to Bordeaux area then inland to the Cevennes and a little past them. I mixed camping in campgrounds with a few airBnB and wild camping. The wild camping was by far the most fun, but mostly because I speak fluent french and asked permission- (so maybe it isn't technically "wild camping"?). Anyhow people were super nice, never got refused, was offered a few meals and I had awesome spots- especially in the plateaus east of the Cevennes and in the mountains themselves. Municipal campgrounds were great- a lot cleaner and nicer than 30 years ago! And they serve craft beer now! ; ) Its rare that there isn't a place for a lone or two cyclists.
I never tried a camper "aire".. I'd not really want to, but I suppose in a pinch one might have to. About the priorité à droite: it's a real subject, mostly because one is rarely faced with it- so when you are, you're taken by surprise - especially in my view when arriving in a small town after being alone all day on country roads. The only negaative thing I'd say (but it's not specific by any means to France) is that there have been agressions (and worse) of cyclists. Maybe just run-ins with the wrong people, but a spanish fellow was murdered last year in the Rhone Valley..I never once had any fear, but my sense is you gotta be smart in general. I would never camp in anything but an official campground or on private property with permission anywhere near a fairly densely or densely inhabited area. Certain areas in the south of France seem sketchier potentially- Rhone valley, the Var, the Medit coast. This could be because of high tourist populations and many secondary country homes left alone, but common sense will def keep you on the safe side. Bonne route! - Peter