Unknown Cross Hallmarks

Hello!I encountered some antique hallmarks wich I have trouble to identify.Any help would be deeply apreciated!

GD with the symbol between in a lozenge is a French silver maker’s mark. I can’t identify it. There should be other marks but I don’t recognise either of the other 2 marks in your picture as part of that French marking system.


Thank you for the reply!
Here are some better photos of the marks.
Unfortuanelly,they are faded.
I’m curious why there is a 7 hallmark and also the number 1 marked above