Large serving Tray 'aux têtes barbues'

Unidentified French silversmith, an important serving tray "aux têtes barbues", 41,5 x 61 cm (handle to handle), marked on the back of the tray, undecipherable makers mark in a lozenge (twice); French export mark ‘Tête de Mercure’ for 800/1000 (in use from 1879-1973).  The makers mark on this magnificent tray is unfortunately eligible.  Either the mark was struck very softly or – and this is more likely – the makers mark was erased by a later retailer. The quality and craftsmanship of this tray points to an important, probably Parisien workshop.