Heat olive oil in a large sauce pan, sauté onion, garlic, zucchini until tender. Stir in the lentils, broth, and pepper. Bring to a boil. Reduce heat; cover and simmer for 20-30 minutes or until lentils are tender.
Stir in the tomatoes, tomato paste, vinegar, basil and oregano. Return to a boil. Reduce heat, cover and simmer for 40-45 minutes