Cook the lentils in the vegetable stock for about 10 minutes and then let them steep for another 5 minutes.
In the meantime, clean and dice the zucchini. Clean the peppers and cut into fine strips. Mix both with the lentils.
Clean the shallots and cut into rings. Sauté in a non-oiled pan. Sprinkle with sugar and deglaze with the red wine. Let everything boil down for approx. 5 minutes. Mix the mustard with the oil, vinegar, salt and pepper and add to the shallots in the pan. Now distribute this warm on the salad. Serve immediately.