Melt butter in medium saucepan on medium high heat. Add onions, bell pepper, and celery and saute' for 5 minutes.
Add cayenne pepper, black pepper, paprika, and garlic and stir well. Stir in white wine and seafood stock, bring to a boil and then reduce heat to low.
Add crawfish tails and salt and mix well. Cover and simmer for 20 minutes. If using shrimp, don't add until the last 5 minutes of the 20.
Gradually add cream cheese until melted, stirring often and cook for 5 minutes.
Add green onions and parsley and a little more white wine if mixture is too thick.
Cut bread in half and scoop out center portion of French bread loaf. Fill bottom portion with crawfish mixture. Place top half on top, brush with melted butter and bake in a 350 degree oven for 15 minutes.