Heat the olive oil in a large pot over medium heat. Add the sliced merguez sausage and cook until browned on both sides, about 5 minutes. Remove the sausage with a slotted spoon and set it aside.
Add the diced onion to the same pot and cook until softened, about 4 minutes. Stir in the minced garlic and cook for 1 minute more.
Sprinkle in the cumin, coriander, cinnamon, and cayenne pepper. Stir for 30 seconds until the spices smell fragrant.
Add the rinsed lentils, diced tomatoes with their juices, vegetable broth, and chopped apricots. Bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 25 minutes until the lentils are tender.
Return the browned sausage to the pot and simmer uncovered for 5 more minutes. Season with salt and black pepper to taste.
Ladle the stew into bowls and top with chopped cilantro. Serve with lemon wedges on the side.