The BBC article about the sale features a photograph of the prayerbook. Although I can't zoom in close or clearly enough to be sure, it looks as though the kneeling man might be a portrait of François himself. In any case, the photograph gives a wonderful view of the intricate artistry of the illumination, as well as the size of the book in relation to the man's hands. The book is expected to sell for about $1,000,000 (500,000 pounds).
Other works in the collection can be viewed here, here, and here. The squirrel on the stand [scroll to the middle set of photos] is precious (although one feels a bit sad for the poor creature).
I must admit that seeing exquisite manuscripts like these make me rue the advent of the printing press just a bit.