The jewel is contained in its original circular brown leather box, the lid satin bearing Eugène Fontenay’s own lid satin with the address ’19 Place du Marché St Honoré / Paris’, premises he first occupied in 1858.
In the rare instances when original boxes for jewels by Eugène Fontenay (1823-1887) survive, they invariably bear the lid satin of the distinguished retailers he supplied with his works, including Frédéric Boucheron and Tiffany & Co. It is extremely unusual to find a jewel by Fontenay in a fitted case with his name and address fully identified.
An identical necklace to this example is reproduced in La Bijouterie Française au XIXe Siècle by Henri Vever, Vol. II, p 169, (translated edition p.639).