the link above has the same see-saw line at the bottom like yours, but I cannot decipher the hallmark on yours as it looks to have been damaged. Good luck!
The zigzag mark is likely an assayer's "mark" (not a true hallmark, just the residual of where the assayer removed a certain amount of metal for assay). This is common in Germany and some other nearby continental countries. Here is an explanation by Blakstone: "The zigzag line, known by the unlikely name of a "diet" in English, is called a "Tremolierstich" in German. (I like the term "proofstrike", which I see occasionally in English translations of German catalogues; much better than the peculiar "diet".) It was produced when an assayer removed a bit of silver with a rowel-like device in order to test the content for purity."
Hello Theoderich,
indeet you are right, thank you very much. The mark was made upsidedown. I have placed your Foto half transparent on my mark and it looks perfekt.