
The Antique Jewelry University website defines it as “Bracelets and necklaces in a style with plaques connected with multiple chains is called en esclavage.”
The website ADIN Fine Antique Jewelry gives this definition:
“Esclavage, French for slavery. A type of necklace composed of three chains or strings of beads or jewels in which the chains or strings hang approximately equidistant from each other. They were worn in Normandy as peasant jewelry in the mid-18th century.”
From the sold archives of One of a Kind Antiques .com was this piece:

The description also give a little history:



Roughly translated from the blog “The collar of slavery, in gold, was in the nineteenth century, the greatest gift a husband can give to his young wife, the Empire or the Restoration.
It usually consists of several chains in festoons, generally has three connected ovals, rectangular, glazed or not.”
This example is from BijouxAnciens:


