In a large saucepan, heat the olive oil over medium-high heat. When hot, add the onion, celery, garlic and fennel. Cook until the vegetables are tender, about 4 minutes. Add the tomatoes and chicken broth and simmer 3 to 4 minutes. Remove from the heat and add the basil and parsley. Puree the soup with an immersion blender or cool slightly and puree in a standard blender. Season with salt and pepper. Serve hot.