Laurence Buffet-Challié, Le Modern Style, Paris, 1975, pp. 48 and 77 (for a related armchair) 
Alastair Duncan, The Paris Salons 1895-1914, Volume III: Furniture, Suffolk, United Kingdom, 1996, p. 212 (for related chairs)

Overall in very good condition. The wooden surfaces with minor surface scratches and scattered minor abrasions consistent with age and gentle use. With light surface dirt to recessed portions of the design. Minor separation of the joints, commensturate with age and use, and does not affect the stability of the armchair. The wood frame with minor areas of discoloration to the recessed portions of the design, particularly to the armrest and upper edge of the back rest, consistent with use. Minor indentation at the center portion of front edge. The leather is likely original and displays a beautiful and finely executed embossed design, harmonious with the overall Art Nouveau aesthetic of the armchair. The surfaces of the leather with some traces of wear, discoloration, surface scratches, cracks and minor losses, consistent with age and use. The leather with a few holes to the edges from a prior affixing of the leather to the frame. A deeply sculptural form further heightened by the intricate embossing of the leather portion of the seat.
In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective qualified opinion.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING CONDITION OF A LOT, ALL LOTS ARE OFFERED AND SOLD "AS IS" IN ACCORDANCE WITH THE CONDITIONS OF SALE PRINTED IN THE CATALOGUE.