I believe Jeff is a freelance jewellery designer for various high-end jewellery retailers?
Pretty sure that I've heard him talk about his freelance associations with retailers on the Place Vendome in Paris. Quick Google lists all the usual suspects and more (Van Cleef, Cartier, Piaget, Graff, Boucheron, Chaumet, Courbet, Chanel...).Good luck to him if he has other strings to his bow - I have an idea he is also a designer (but of what? Jewellery?). Could be wrong with this.