Season flour with salt and pepper; dust chicken pieces with seasoned flour.
Heat butter and olive oil in a large frying pan over medium-high heat. Place chicken pieces in frying pan; cook, turning once, to brown on both sides, about 6 minutes.
Stir in eschalots, 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, salt and pepper. Cover and cook over medium heat for 12 to 15 minutes.