Cut the bacon into medium-sized (about 1/2 inch) pieces. Cook it over high heat until it turns golden brown.
Reduce the heat to medium, remove the bacon, and set aside. To the same pot, add the carrot, onion, and bell pepper.
Cook, stirring occasionally, for about 10 minutes, or until the vegetables begin to soften.
Add the tomato paste and paprika, and cook for another 5 minutes.
Add the lentils, water, and bay leaves. Cover with a lid and cook for 30 minutes.
After the soup is cooked through, remove the bay leaves and discard. Using an immersion blender, puree the soup until smooth. Add salt to taste.
Serve the soup topped with the reserved bacon pieces and freshly chopped scallion.