Heat the olive oil in a large pot over medium heat. Add the onion, carrots, and celery and cook for 5 minutes until the vegetables start to soften.
Stir in the garlic, thyme, and smoked paprika. Cook for 1 minute until the garlic becomes fragrant.
Add the lentils, vegetable broth, and diced tomatoes with their juices. Bring the mixture to a boil, then reduce the heat and simmer uncovered for 25 minutes.
Stir in the chopped kale and continue cooking for 5 more minutes until the kale wilts and the lentils are tender.
Season with salt and black pepper to taste before serving.