The badge says  "Maschinne Naumann. Seidel & Naumann, Dresden”.
Another Naumann badge, silvered.

 

NAUMANN ca. 1920

Serial #: 2.351.189

Condition: Working

With a look of early Singer 15k and the butterflies decals of the 28K, this example is a interesting eclectic model.

 Seidel was the financial partner of Bruno Naumann, who started manufacturing, in Dresden, Germany, in 1876. Factory had 8.000 workers when expropriated after WW2. Brands Naumann, Ideal and Erika are still in the market.  (ISMACS, issue 8).

To know more:

Bruno Naumann History.   www.ismacs.net/sn/naumann.html

Instructions for  Naumann sewing machines   www.demon.co.uk/quinn/naumann/index.html

Naumann Gladys  model . www.demon.co.uk/quinn/nauman/index.html

An example ca. 1890 in: http://home.sol.no/~astaal/SANDN.HTML