Chicken with Peach Sauce

Ingredients (for 2 people):

– 2 pieces of chicken (preferably with bones, which are more tasty)
– ½ lemon
– 2 tablespoons of harissa
– 1 tablespoon of rosemary
– Sesame oil
– 1 onion
– 2 sticks of celery
– 1 green pepper
– 1 preserved peach with syrup