Easy recipe:

3 tablespoons extra–virgin olive oil
2 cups chopped onions
1 cup chopped celery stalks plus chopped celery leaves for garnish
1 cup chopped carrots
2 garlic cloves, chopped
4 cups (or more) vegetable broth
1 1/4 cups lentils, rinsed, drained
1 14 1/2–ounce can diced tomatoes in juice
Balsamic vinegar, ham or sausages (optional)

Heat oil in heavy large saucepan over medium–high heat. Add onions, celery, carrots, and garlic; sauté until vegetables begin to brown, about 15 minutes. Add 4 cups broth, lentils, and tomatoes with juice and bring to boil. Reduce heat to medium–low, cover, and simmer until lentils are tender, about 35 minutes.

Transfer 2 cups soup to blender and puree until slightly lumpy – don’t over swirl and make it into babyfood. Return puree to soup in pan; thin soup with more broth by 1/4 cupfuls, if too thick. Season with salt, pepper, and a splash of vinegar, if desired. For non-vegetarians consider adding some sausage or ham. Ladle soup into bowls. Garnish with celery or cilantro leaves.

Suggest peppery Bob’s Redmill petite green lentils. buy them here

FYI:

With 25% protein,  the lentil is the vegetable with the highest level of protein other than soybeans.

Provides  antioxidants such as Vitamin A and Vitamin C, which bind with and destroy free radicals, reducing oxidative damage to cells.

Have high content of tannins, phytochemicals that prevent cancer growth, making them a good addition to any diet.

Good source of important minerals like iron, magnesium, and zinc. Iron deficiency causes anemia while zinc is one of several nutrients necessary for fending off infections.

Where to get a good  bowl of lentil soup in Paris?

Restaurant Dominique Bouchet
11 rue Treilhard, 8th arr.

Les Papilles 30 RUE GAY LUSSAC
5th arr (not always on the menu) – their delicious cauliflower soup an alternative