Here it is a quite standard French silver fork.
According to the marks, this fork was made in Paris between 1798 and 1809 ("first cock" mark).


The silversmith mark is : AL surmounted by an oak leaf ?, above a compass (or a third letter ?) ?, in a losenge.
I have not identfied it yet, since I do not have immediate access to Arminjon's book on 19e s. Parisian silversmith marks. Indication on this silversmith mark would be of course appreciated.
Nevertheless, there is another mark, alone on the other side of the fork, which suprise me.

This mark seems to be FG (this typo is often called "anglaises" in French, I do not know the proper translation into English !) in an oval.
I think that I have already seen this mark once, several years ago, probably on a 19e c. silver item - I do not remember clearly.
Any idea on this mark ?