Season flour with salt and pepper; coat chicken pieces with seasoned flour.
Heat butter and olive oil in a large skillet over medium-high heat. Place chicken pieces in skillet; cook, turning once, to brown on both sides, about 6 minutes.
Stir in shallots, onions, and garlic; cook until soft, about 3 minutes. Stir in tomatoes and wine; bring to a boil. Then stir in saffron, curry powder, sugar, raisins, and salt and pepper. Cover, and cook over medium heat for 12 to 15 minutes.