Upvote:4
After visiting another antique market I now know more about the hallmarks:
The 8 star 4 either means that the 84% of the material used is not silver but some other metals - in other words the metal mixture contains 16% silver. Or, not my case, is would be mean that 84 grams of silver have been used to create the set of objects. This is usually marked with a 84g-hallmark which seems often misread as 840 or 849 - leading then to the conclusion that is 840/1000 silver.
I still don't know which makes J B and haven't yet understood the meaning of the other hallmark.