Cook the chopped bacon in a large pot over medium heat until lightly crisp, about 5 minutes. Remove and set aside, leaving the rendered fat in the pot.
Add olive oil if needed. Sauté the onion, carrots, and celery until softened, about 5 to 7 minutes.
Stir in the garlic and cook for 30 seconds.
Add lentils, diced tomatoes, broth, cumin, paprika, bay leaves, salt, and pepper. Stir to combine.
Bring to a boil, then reduce to a simmer. Cover and cook for 30 to 40 minutes, or until the lentils are tender.
Stir in the cooked bacon and vinegar. Simmer for 3 to 5 more minutes.
Remove bay leaves. Taste and adjust seasoning.
Garnish with chopped cilantro or parsley and serve.