As I continued to investigate on Jean de Voyod, I found that another eBay seller is offering another de Voyod album at 8,500 euros:
http://www.befr.ebay.be/itm/Russland-Militarfliegerei-Gatchina-Fotoalbum-J-De-Voyo-1912-/251762653801
This album came before the other and roughly covers the period 1917-1923. The page is highly informative and full of images (reproduced below) but translating it would take a while as it is entirely in Russian.
It is the same album that was previously presented in auction catalogs of Russian art from Cazo, a French auction company, with a few pics and info:
http://www.cazo.fr/wp-content/uploads/2015/10/CATA_AR_22042015.pdf
http://www.cazo.fr/wp-content/uploads/2015/11/Catalogue-Art-Russe-12-2015-W.pdf
This page from La gazette Drouot (the official publication of l'Hôtel des ventes Drouot, France's equivalent to Sotheby's) also features what seems to be the same album, with a text that gives similar information:
http://catalogue.gazette-drouot.com/ref/lot-ventes-aux-encheres.jsp?id=5001463
The two albums can be found in other auction sites on the web, sometimes with slightly different images offered. The following was especially interesting as it provided a decent size version of the Sesquiplan being built:
http://www.the-saleroom.com/de-de/auction-catalogues/nosbsch-and-stucke-gmbh-auktionen-berlin/catalogue-id-srnos10003/lot-ecd6db10-2f7f-496a-a2ab-a514016e1bed
So, let's try to summarize what we've got from these various sources:
Jean de Voyod definitely was a Frenchman. He is described in these sources variously as "a Russian aviator of French origin" or "a Russian WW1 ace of French origin", but the fact he was a "Russian pilot" or a "Russian ace" does not preclude his being 100% French. Many aviators served under different flags during various wars—think for instance of the many foreigners in Spain's civil war.
In 1917, he was a flying ace of the Imperial Russian Army as part of Colonel Krouten's regiment, then as part of the Kamenetsk-Podolsk squadron, and in 1918 as part of Kolchak's army. As an aviator who had emigrated to China, he came into service with Chinese aviation, until his return to France, being a member of l'Aéro-club français.
Besides many photos of individuals (a lot of Russian officers, notably) the "Russian" album includes the military aviation school in Gachina (1912-16), Gachina airfield, the christening of Sikorsky's "Ilya Muromets" in Gachina in 1916, the accidental landing of the same with Sikorsky at the controls, Korpusnoye military school airfield, the city of Omsk photographed in 1918 from a plane, Moukden in 1923-24 (where construction of the Sesquiplan pursuit took place), as well various aircraft types such as the Farman Type XVI and Type IV, a Russian-modified Daimler Albatros or the first "Voisin-canon".