François Boucher Or Entourage (1703-1770) "woman's Head"

François Boucher or entourage (1703-1770)
"Head of a woman"
Drawing on laid paper.
Black stone and pastel highlights.
Pretty Louis XV style frame (small gaps).
Unsigned. Attributed to F.Boucher according to the public sale catalogs of 1922 and 1969.
Can also be attributed to Louis-Marin BONNET, engraver of F.Boucher.
Label mentioning: "Marquis de Varennes Collection - May 1922 Sale
René Kieffer Collection - May 1969 Sale"
Attached (see photos) are screen copies of the catalogs for the Marquis de Varennes sale and that of René Kieffer's sale.
On the back handwritten note "Original drawing by François Boucher, black chalk and pastel highlights. 1703-1770"
The superposition of photos of the original drawing and photos from the catalogs show their absolute similarity, right down to the lines of the parallel ribs of the laid paper which overlap perfectly.
Dimensions at sight: 20.5 cm x 15.5 cm
Overall dimensions: 35 cm x 30 cm