A seated academic nude with his hands clasped

We thank Professor Jean-Luc Bordeaux for kindly confirming the attribution. He points out that the inscription is by the same hand as those on other drawings by the artist which mostly date from his sojourn in Italy in 1724, or not long after his return to France (J.-L. Bordeaux, François Lemoyne and his generation, Paris, 1984, D8, D38, D45, D54, D57-D60).
This might be an early study for The Transfiguration painted in 1723-4 on the ceiling of the Chapel Saint-Louis in Church of Saint-Thomas d'Aquin, Paris.