Here is a similar decorated bichaq in Balkan form next to the Tunisian dagger. Notice how the coral and brass inlays are almost identical between the two. Could the Bizerte dagger's decoration have been influenced from across the Mediterranean from Ottoman times and trade? Posted also is another closely related example from Oriental arms described as Mediterranean
/Balkan and dated 1278 (1861).
Link:
http://oriental-arms.co.il/item.php?id=5845
-Geoff