Here is a silver fork, and its marks.
Based on these mark, including the number 34 on the "garantie" mark (a bearded man in front), I think that this fork was made in Mons (Belgium) between 1798-1809.
As we konw, at that time Belgium was controlled by France, so these are French marks.
The silvermith mark is A, a dot, D in a rectangle (the dot is not very clear on the picture, but I am pretty sure of it existence when I directly look at the mark).
Interesting to note that this Belgian silversmith mark does not meet French official regulation of the time, under which silvermisth marks should be included in a lozenge. I suppose that in countries occupied by France, (at last some of the) silvermiths already installed keep their previous mark in order to avoid fabrication cost of a new punches, whereas new silversmith used losenge-shape marks. I do not know if silvermiths of occupied territories like Belgium (and later parts of was is now Germany, Swizerland and Italy) had an official authorisation allowing other-that-lozenge-shaped mark during this period, or if it was just a sort of "tolerance" from French authorities.
As you can guess, I would be pleased to know the name of this silvermith.
Thanks for your help !