Thanks for the hint. I can see some lines now. But the drawing is not complete (Demo version).
Until now I import the dxf12 in OpenOffice Draw and export the SVG. This solution is not perfect. The svg drawing just looks in the begining good. if I go closer, I can see that some angles and lines are not 100% perfect. I need also to convert a lot of dxf files in the future. So the OO solution is not working for me.
For this reasons I think about to buy the license of qCad. But I would like to be sure that the SVG-output is that what I need. So if you please could send me the SVG as PN I could check this.
Thanks for your help,