I'm in the middle of wiring up a cable for an electrical hook up to be
used while camping in France. I have a French 3-pin plug bought there
on a previous visit, but in opening it up I find there's absolutely no
indication which of the two power pins is live and neutral. Doesn't it
matter?

I will be using the cable with an RCD device; won't that object and trip
out if the wiring's the wrong way round? Or is it a case of "suck it
and see" when I get to France, and if it's wrong, reverse the wiring?

Thanks
David