French maker mark on a confiturière

These are marks on a very pretty french confiturière. Can someone please help me with this maker mark? It is impossibile for me to solve it.

According to Tardy, International Hallmarks on Silver, your marks date to the period 1798 to 1809. The rooster mark denotes 950 fineness and Paris. The other mark is the Garantie I don’t know who your JG marker is. Hope this helps. Nice piece!