Heat the oven to 350 degrees. Check the crab meat for shells, being careful not break it up too much. Squeeze handfuls of the crab meat gently to get rid of any excess moisture and set aside in a medium bowl.
In another bowl, combine the mayonnaise, cream cheese, mustard, creme fraiche, 1/4 cup parmesan, cayenne and salt and pepper to taste. Stir until smooth. Stir in the scallions and gently fold in the crabmeat until just combined. Taste and add more salt if necessary.
Spoon the crab mixture into a shallow oven-proof serving dish. Sprinkle more parmesan over the top to cover, followed by a dusting of paprika. Cover with foil and bake for 15 minutes, until warmed through. Uncover the dip, turn on the broiler and broil until the top is golden brown, watching carefully. Let sit for a few minutes to cool slightly before serving with water crackers, Triscuits or toast points.