1. Place crème fraîche in a medium bowl; beat with a mixer at high speed until stiff peaks form. Add 1/2 teaspoon matcha, lemon juice, 1/8 teaspoon salt, and paprika, stirring with a whisk.
2. Combine remaining 3/4 teaspoon matcha and ground ginger in a fine mesh sieve over a bowl; press ginger mixture through sieve. Sprinkle the ginger mixture evenly over scallops.
3. Heat a large heavy skillet over high heat. Add 1 1/2 teaspoons oil to pan; swirl to coat. Arrange half of scallops in a single layer in pan; cook 2 minutes on each side or until browned and desired degree of doneness. Remove scallops from pan. Repeat procedure with remaining 1 1/2 teaspoons oil and scallops. Arrange 3 scallops and about 1 tablespoon crème fraîche mixture on each of 6 plates. Sprinkle evenly with fleur de sel and chervil, if desired.