Remove the beards from the mussels; wash the mussels and clams; peel the shrimp and remove their veins. Heat the olive oil in a heavy skillet. Add the shallots and garlic, saute until they are translucent. Add the basil, fennel, hot pepper and saffron, saute for 1 minute. Add the orange zest, diced tomatoes, tomato puree, white wine, stock, salt, pepper and clams. Cover the pan and simmer it for about 5 minutes or until the clams begin to open. Add the mussels and shrimp and simmer it another couple of minutes just until the mussels open and the shrimp are cooked. Divide the shellfish into 2 or 4 warm bowls and pour the broth over the shellfish. Serve with sliced French bread croutons.