He opened his eponymous boutique at 16 Place Vendôme, the heart of French fine jewellery, in 1922 and registered his mark the following year. Success followed quickly, aided by his frequent advertisements in popular magazines such as Femina and Vogue and he soon established a reputation for fine quality pieces of both jewellery and objet d’art.
He was influenced by his time in India both artistically and in his choice of stones, producing some exceptional jewels in the ‘Tutti Frutti’ style. Richly coloured carved rubies, sapphires and emeralds were set against the bright sparkle of diamonds in a range of flora inspired designs including stylised flowers, leaves, fruit and berries. Alongside Cartier and Mauboussin, Ostertag produced some of the finest examples of this style of jewellery during the 20s and 30s. Alongside jewellery he also sold an extensive range of accessories such as vanity cases, cigarette cases and compacts as well as boxes and other objet d’art. Decorative hardstones such as agates, lapis lazuli and jade would be embellished with ruby and sapphire cabochons and diamond highlights making them miniature jewelled works of art.
Beautifully designed and crafted watches were made in gold and set with a variety of precious gems with movements supplied by experts such as Vacheron Constantin, Audemars Piguet and Baume et Mercier. Clocks were supplied by the renowned firm of Verger-Frères, Georges Verger being one of very few people who knew the secret of the ‘Mystery Clocks’ which both Ostertag and Cartier sold. Verger were just one of a wide cast of renowned yet discreet workshops that supplied Ostertag, another being Rubel Frères.
In 1929 Ostertag exhibited jewellery and objet at the Musée Galliera alongside Boucheron, Fouquet, Van Cleef & Arpels and Mauboussin with ‘Le Figaro’ publishing a special supplement illustrating a selection of the jewels on display. These included a stunning Tutti Frutti bracelet and brooch by Ostertag as well as a necklace centred with an exceptional round faceted sapphire and striking Art Deco style clips.
In 1937 the opera singer and film star Grace Moore wore a beautiful diamond Ostertag necklace for a debut concert at Carnegie Hall. It was reported at the time that the baguette diamond set in the middle had originally been cut from the Cullinan diamond and this suspended an unusual kite shape diamond in a geometric surround, all from a round and baguette diamond necklace.
Arnold married his American wife Verna in Paris in August 1939; he was 56 and she 25. They had met in Cannes two years previously where Arnold had a second branch of the firm. Just over a month after their wedding, war was declared and Verna immediately returned to America. Arnold followed her a couple of months later in November leaving the management of the company to a trusted employee, Mr Foa. Sadly Arnold never returned to Paris, he died in April 1940 less than six months after arriving in the States, leaving his entire estate to his wife. Back in France, Paris had been Occupied and business had virtually ground to a halt, the firm finally and formally closed its doors in 1941.
Despite its relatively short existence, Ostertag made a significant contribution to the history of French jewels during the 1920s and 30s and the Maison’s mark remains a sign of style and quality.