Well, as far as animated series based on Franco-Belgian comics go, I have to confess that I harbor certain fondness for the 90's adaption of Tintin and Blake & Mortimer. They're not as good as the comics they're based on, but are still quite decent, if you ask me.
I would also recommend Night Hood, which takes Maurice Leblanc's archetypical gentleman-thief, Arsene Lupin and puts him in the 1930's. Thoroughly enjoyable show, with a very charismatic main character.