|Thanks for the advice, Ronan. I've read the extract available on the BnF Gallica website: https://gallica.bnf.fr/ark:/12148/bpt6k33458014.texteImage
I've not had any luck, however, in getting hold of the original publication or even a pdf copy of the full essay. I tried buying a pdf on various French websites, but was refused as soon as it became clear I didn't live in France. For some reason they cannot sell digital scans outside France.
I'll just have to keep checking Abebooks, ZVAB, and all the usual suspects.