Puckerings has dated this piece to the 1930s.
The sterling silver collar is stamped with the poinçon minerve for sterling silver. The silver is singed by the top-notch sivlersmith, Keller Paris. I have included some information below for this famous company.

About as stylish as they come in excellent condition. 9" tall x 5 1/2" in diameter. Art Deco in era dating to c.1930.
Gustave Keller
The Keller firm was founded in 1856 by Gustave Keller, whose simple yet elegant sets and accessories were immediately appreciated for their quality. He was awarded a gold and a silver medal at the 1867 and 1878 Paris World Exhibitions. After 1878, the Keller brothers succeeded him and started producing silverware, which was rewarded at the 1889 and 1900 world fairs respectively, with a gold medal and a Grand Prix. In 1889, Lucien Falize wrote that "everything stamped Keller is good" (the firm was later known as "Keller fils et gendre successeurs"). Established in Paris at 65 rue de Turbigo, Keller moved their shop and workshop to 22 rue Joubert in 1891. In 1929, the shop was mentioned as trading from 18 Avenue Matignon and was still active possibly as late as 1947. Keller attracted brilliant and international customers and was appointed official supplier of several courts (Spain, Russia, Greece and Romania). The Russian Court was an important client and from 1897, the last Tsar regularly purchased artifacts from the Parisian silversmith. From the 1900s the firm was also commissioned to produce several important cups and trophies for the Principality of Monaco.
Item ID: 49867
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Puckerings has dated this piece to the 1930s.
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