Add 2 tsp of olive oil to a large sauté pan. Add the diced onion, diced shallots, and red pepper flakes to the pan and sauté over medium-high heat, while mixing often, until tender, about 6 minutes. Add the chicken stock and lemon juice and boil about 5 minutes. Add the Marzano tomatoes with their juices, and top with 1 tsp dried basil, ½ tsp herbs de provence, and salt and pepper to taste. Reduce the stovetop heat to medium and simmer for 10 minutes. Make sure to push down on the tomatoes until they break up.
Season the fish with ¼ tsp salt, ¼ tsp black pepper, and ½ tsp herbs de provence. Add the fish to the pan and cover each piece in the sauce. Cover the pan and simmer until the fish is almost cooked through, about 4 minutes. Flip each fish piece over, add the olives and marjoram to the pan, mix, and let everything simmer until the fish is cooked all the way through, about 2 minutes.
Remove the fish from the sauce, remove the skin (it should be easy to remove once the fish is cooked through), and then put the fish back into sauce prior to serving.