I have these French codes in the ‘Repertoire des sigles ateliers - Forces armées françaises - 1987’ (but not sure those are the same as in the 1890-1920’ periode):
R= Ste. Trefileries & Laminoirs du Havre, Rugles, France
RNN= Ets. Rabourdin, Noisy le Grand, France
R= Ste. Trefileries & Laminoirs du Havre, Rugles, France - i think it was the same in 18xx, french wiki says this manufacturer was since end of 18xx.
But RNN manufacturer was opened after 1950
Does your book says anything about RN? I think RNN on my shell is mistake, just doubling “N” by the mistake.
The French RN code is not mentionned in the 1987 book.
Looking closer at your picture, couldn’t it be ‘RM’ ? that one exists: Ets. R. Merat, Suresnes, France.
Yes, it can be RM! 1 post photo is very real shows how it looks.
Google dont know anything about this manufacturer (maybe it was closed year ago), so it could be from 1898.