While Midge Maisel (Rachel Brosnahan) is walking through the beauty department at B. Altman, we get a glimpse of two factice bottles. The tallest one is Rochas Madame Rochas; the one with the squared black stopper is an eau by Lanvin (it could be either Arpege or My Sin).

In front of the Femme Rochas, there is a huge bottle with black square cap, I doubt that may be Arpège Eau de Lanvin (or My Sin, Scandal, Pretexte, Crescendo, etc. for all the above share the same bottle design).
I think it’s a Lanvin eau exactly for the same reason. Why do you think it can’t be it? Wasn’t that bottle design used for Lanvin eaux?