Ivo, this may not be much help, but here goes. There is a book 5,000 open salts by Wiliam Heacock and Patricia Johnson. In the book is shown a page of lacy salts found in an 1840 catalogue of Launay, Hautin et Cie, a French company distributing the glass of Baccarat, St. Louis and other lesser known glass houses. I quoted from the book. One of the salts appears to be identical to yours. So IMHO at least we know its French. Terry