Fry both in a saucepan until the onions are translucent. If you want to remove the bacon before eating, you should cut it into large pieces.
Peel and dice the soup greens, without the parsley, and the garlic. Add the vegetables to the onions and sauté briefly. Then add the tomato paste and sauté briefly. Add the tomatoes, vegetable stock and lentils. Simmer for 20-30 minutes until the lentils are cooked through.
Chop the parsley and add to the soup or sprinkle it on the soup on the plate.