Unidentified sewing machine

Unidentified sewing machine purchased in Germany. It contains a golden plaque with the initials BR under a crown. The measures of the base are: 32,1 x 16,6 cm. It looks like a 48K Singer or a Frister and Rossmann, but it has some differences that make me doubt and not be able to say it. It has a decoration made with square spirals and at the base has remains of what would be a flower made of mother-of-pearl or mother-of-pearl. I would appreciate the help that I can provide to know what kind of sewing machine it is. Thank you very much in advance. Sincerely.