"This client - she chose everything and she wore everything. It's very intimate," Christie's auctioneer Camille de Foresta said.
The most valued item in the sale is a purple velvet dress designed by Lagerfeld for Chanel for the 1988 winter collection.
Estimated at 4,000 to 6,000 euros, the Tudor-inspired dress is embroidered with gold thread and beads by the French atelier Lesage, and sports a removable satin collar - a Lagerfeld trademark.
The auction also features several Yves Saint Laurent creations, including a gold lame encrusted tunic and matching pants, a nod to the designer's love for Moroccan culture.
A velvet bustier evening dress, from Saint Laurent's 1984-1985 haute couture collection, is also up for sale.
"The client loved Saint Laurent. And you know, all haute couture clients, they said that the Saint Laurent outfits are the most comfortable and the more feminine and sensual," de Foresta said.
The Parisian owner also wore pieces by Christian Lacroix, Gianfranco Ferre for Dior and Valentino, and most of the couture pieces were bought in the 1980s and 1990s.
Christie's haute couture auction - which started on 11 January and runs until 25 January - has been attracting mostly fashion and decorative art museums as well as the fashion houses themselves seeking to fill their archives.
Haute Couture Fashion Week, which wraps up on Thursday, allows an elite club of top-end designers to show off elaborate creations, which are not mass-produced for stores but tend to be sold to private clients.