Check the lentils for stones or any foreign objects.
Place the lentils in a container, cover with plenty water and let them soak for a couple hours.
In a bowl mix all the spices for the Cajun seasoning.
Pad dry the ribs with paper towel and mix with 2½ teaspoons Cajun seasoning. Let them marinate for 1 hour. Save the rest of the seasoning for other Cajun recipes.

Cut the vegetables and measure the rest of the ingredients.
Heat up at moderate temperature a large frying pan and melt the pork fat. When some of the fat becomes brown, remove and reserve.
Place the ribs in the frying pan and brown them on both sides. Remove to a deep pot.

Add to the frying pan onion, garlic and brown them, trying to lose any particles sticking on the pan.
Add the rest of the vegetables, brown pieces of pork fat and sweat them for 3 minutes.
Add 1 teaspoon Cajun seasoning and cook for 1 minute. Add the vegetables and tomatoes to the pot with the ribs.

Deglaze the frying pan with the wine or water and add to the ribs.
Incorporate the water, bring it to a boil, lower the flame and let the ribs cook slowly for 45 minutes.
Drain the soaking lentils. Add lentils, potatoes to ribs in the pot.
Let boil the liquid, lower the flame and cook slowly for 25 to 30 minutes or until lentils are soft.

Serve the soup with a bit chopped tomatoes and cilantro on top.