Heat the olive oil in a large frying pan or wok. Add the chopped onion and saute over medium heat for 5 minutes, or until the onion softens. Turn up the heat to high, add the bell peppers and shrimp and saute until shrimp is fully cooked, about 3 minutes on high heat. Add the sliced sausage and stir to heat through. Remove from heat and garnish with fresh herbs.