This is posted in response to David's mystery piece and organ. I don't have Marchand's first book handy, but I found this untitled Cromorne en Taille at the end of the 5th organ book, and sight read it using the same registration David used in his "mystery piece" just before this.
So at least we know the organ... The piece should be easy enough to find on IMSLP or similar. It is lovely, so it would be nice to know where it is found.
GO: Montre, Bourdon, Tremb. doux
R: Cromorne, Bourdon
P: Fluste 8 (and playing GO stops)