An unknown work by Simon Marmion?

Caen enchères, from France, sells on 7 October 2017 a "Simon Marmion" fragment of a painting showing King Solomon(?). Measuring 27,5 by 17cm, it is estimated at 12,000 to 15,000 Euro.

Simon Marmion (1420-1489) is an Early Netherlandish painter from the Bruges school (although he is anative of the Northern French city Valenciennes, and worked mainly in the other northern French city Amiens). He is best known as one of the best miniaturists of his period, but some paintings from his hand are also known (e.g. in the Philadelphia Museum of Art, the Met, and the National Gallery in London). While he is as a a painter not as important or good as Van der Weyden or Memling, he still is one of the main painters of the period.

No works attributed to Marmion have been sold in the last few decades, it seems, so to have a real Marmion for sale would be a major, major find. The work for sale is only a small fragment, and in rather poor condition. Even so, it seems to me to be a work by a follower of Marmion, a work in his style but not precise enough to be really by him.

Concerning the topic of the painting, I don't immediately see a reason why Solomon would be depicted next to a fountain. More likely is that this is king David looking at Bathsheba, bathing or washing at the fountain. Even though Dvaid is usually shown from a window, balcony, or roof of his palace, it is not unique to have him closer to the action.

Comparing it with similar details from paintings and miniatures shows that Marmion, at this small scale, was a better artist, adding even the smallest detail with incredible care.

Compare e.g. this Mass of St. Gregory, from the Art Gallery of Ontario, with the work for sale. This work is 45cm by 29cm, so not really big either. Still, minute details like the head of Saint Gregory are given with infinite care. It is comparable in scale to the figure of King Solomon in the work for sale, but the difference in quality is remarkable.

Works from his circle have been sold over the last 25 years for prices ranging from 6000 Euro to more than 150,000 Euro, so the estimate for this one may still be spot on. If it were a real Marmion, even in this condition, it should be worth considerably more as they are incredibly rare. But in my view it should be described as a Follower of Marmion instead.

UPDATE: sold for 13,200 Euro, and may be bought by the Museum of Picardy in Amiens. If it is real, it will probably be one of the oldest works in their collection, and for a reasonable amount of money.