The crowned E is the french guaranty hallmark in use in Paris between 1809 and 1819 showing that the item was from foreign origin. Regarding the middle hallmark I cannot really figure out exactly what it is. AZ for me is the maker's mark.
the middle mark is indeed the mark of Hamburg. It´s the three tower
and gate mark but he´s a bit messed up ;)
The first mark is the mark of France that the object is imported to France from another country. It´s a guarantee mark that the object really is made of silver.
The third mark is the makers mark, but I don´t know who the mark belongs to. sorry.
Dear janwh, there is only one known Hamburg goldsmith who used the 'AZ' in a rectangle: August Heinrich Friederich Zwicker. He was born around 1770 and died in June 1832. He was active in Hamburg since around 1802 until his death. Maybe he is the guy. Best wishes, Bahner