Hi
The rhombus-form mark looks like marks used in France for silversmith from 1798 to now.
But :
1. The silversmith mark should be accompanied by two other marks : garantee hallmark and title hallmark
See examples below :
http://www.925-1000.com/Ffrench_marks.html
2. The "800" inscribed on the ladle is uncommon for French silver (in fact, title hallmark specify the purity : 800 or 950/1000).
The number could have been inscribed by the silversmith for export, but that only an hypothesis.