(This one depicts the actress and dancer Loie
Fuller who was a redhead in real life too)
(Saxoléine, Pétrole de sureté - which
I'm guessing is an advert for lamp oil)
(A poster for the novel The Lover of Dancers
by the French writer Félicien Champsaur)
(An advertisement for drinks I'm guessing
..can be found in all great cafes)
This next one, which is quite stylish, and I guess more in the Art Nouveau style, is by the artist Koloman Moser.
(Vorfrühling, meaning "Early spring".
From the magazine Ver Sacrum)
The following image depicts the French cabaret singer and actress Yvette Guilbert, and is by the Swiss-born artist Théophile Steinlen.
There are several other images that also show her with red hair, however it seems that it was a product of dyeing.
"She accentuated her physical features by whitening her face, dying her hair a striking shade of red, and wearing shoulder-length black gloves."https://www.encyclopedia.com
Though whether she dyed it to further redden it or to change it completely I've not yet been able to discover.
(This one comes courtesy of the above
mentioned Jules Chéret)
(..and this one of her
is by Toulouse-Lautrec)
I also came across this striking Toulouse-Lautrec image featuring another red-haired woman.
(Red-Haired Woman on a Sofa