This series of preliminary sketches for Prélude charnel, a commission that was never followed through to finished plates, is reproduced here with thanks to The Erotica Bibliophile website and to Georges Pironet. They were probably intended for the 1957 Deux-Rives edition, which was in the event illustrated by Édouard Chimot, though they also have the feel of being rather earlier.
What is most interesting about these sketches is that they show how Paul-Émile Bécat worked as he developed ideas for a book project; these are almost certainly the sketches he would have shown the publisher before receiving final approval to proceed. Each has a page reference to show where it falls in the text.
The complex publishing history of Prélude charnel can be found in the themes and topics section.