old French telephone by ERICSSON

This old telephone was apparently made by the French subsidiary of the Swedish ERICSSON company, sometime in the 1st half of the 1900's. It has a (nickel?) plated tag on one end stamped with "SOCIETE DES TELEPHONES ERICSSON COLOMBES (Seine)" and that lettering also appears stamped on its 'handset' (with the number 72841) and on its separate 'earpiece' (with the number 75976). There is a 3 position switch on its top labeled "GARDE" and "AUTOM" as well as a small unlabeled pushbutton. Its case seems to be made of black crinkle-finished steel, which looks like it used to have a thin double-line "border" pattern in a gold color stenciled around the edges of its 4 sides.

I do not know exactly how old it is, nor really what the purpose of its 2nd 'earpiece' (or the switches, for that matter) would have been.