Bring a large pot of salted water to a boil. Add the carrots and boil until tender, about 15 minutes. Let cool slightly, then slice into 1/2-inch coins.
In a large bowl, whisk the olive oil, harissa, garlic, lemon juice, 3/4 teaspoon salt and some pepper. Toss with the carrots to coat, then toss with the cilantro and parsley. Sprinkle with the sesame seeds and serve warm or at room temp, or refrigerate until ready to serve.