There's a couple of mentions here.  Refering I think to Krumholtz "The Complete Gillette Collector's Handbook":
in the chapter "Gillette Clones" mentions German manufacturers Linden, Otto, Optimo, Heco, Melito, Rotbart, FATA, Theo. Offenbach, Fraenkel, Fred. Middledorf, Rohoppf, Meehan, Koening, Hennico, Enn Werke, Befa, Loew, as well as Merkur.