Combine lentils and 4 cups of water in a large saucepan. Bring to a boil and then reduce heat to low; simmer for about 20 minutes or until lentils are soft enough to eat, but still firm. Remove from heat and drain.
In a large bowl, whisk together vinegar, olive oil, garlic, salt and pepper. Add lentils, zucchini, red pepper, and herbs and stir until combined. For best flavor, refrigerate at least 3 hours before serving.
If you can't find French lentils, use brown lentils and follow the cooking instructions on the package.