Please read Alexey Sklyarenko's annotations on Pale Fire, Ada and other Nabokov works here.
Describing the torments of poor mad Aqua (the twin sister of Marina, Van’s, Ada’s and Lucette’s mother), Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions Aqua's talc powder (now used by Marina) in a half-full glass container marked colorfully Quelques Fleurs: