His firm also produced cigarette cards and according to Wiki used a mark consisting of a star with trailing comet tail. Though I haven't seen this, this makes it pretty likely that the "shooting star" card below is an Étoile production.
In 1903 Gaston Piprot was president of the Chambre Syndicale de la Carte Post Illustrée, and he remained a vice president for many years.
There is an article on Piprot here on French Wikipedia, which has detailed references. All the illustrations have been removed by a robot because of inadequate copyright information, but thay are accessible via one of the references at google.com/albumarchive/.......
Piprot has an entry in the 1914 directory but the Etoile marque is shown under the Fargeon name as exclusive agent. During the WW1 visé regulations many cards show that they were printed by Piprot, or by Établissements photographique de Boulogne-ser-Seine, which must have been a Piprot business. The demand for cards boomed and a number of new publishers started at that time. Publishers with Piprot print lines include Dix, E.M., JM, MJ, Rob and Suzy. These marques often have different print lines on different cards,
By 1921 the card business, with that of E David, had passed to A Monod, who advertised just the marques Dix, Diane and Idole. See the separate entry here for Éditions Lafayette, eg under the DIX logo.
By 1925 a slightly tilted star became a marque of A.M.Weiss (Spécialités pour l'exportation, Beautés, Enfants, Amourettes, Décolleté, Fantaisie) at 28 r.Dechabrol.