The Dewoitine HD.730 floatplane was to be catapult launched and recovered by crane I believe. I would assume the handrails were to provide grips for the crew as they attached the aircraft to the crane after landing and while still on the water's surface. I know other crane-recovered floatplanes did not have such robust handrails, but it is French after all.
Hell's teeth, that was quick! And well done!
Yes, it's a Beech 18, or C-45 Expeditor, tail light assembly, this one seen in TFC's hangar at Duxford earlier this year.
Take it away!
I know right? You post something thinking "Ha, this will take a while" only to have someone swoop in and nail it (you all are very good). Well, here is my next "this will take a while" effort...