Add bacon and olive to a Dutch oven over medium heat.
Cook, turning occasionally, until bacon is crispy, about 7 minutes.
Use a slotted spoon to transfer bacon from pan to a paper towel–lined plate. Set aside.
Add onion to bacon drippings in pan. Cook, stirring occasionally, until onion begins to caramelize, about 15 minutes.
Add carrots, salt, pepper, nutmeg, and garlic; cook, stirring often, 1 minute.
Add wine; stir to release any browned bits from bottom of pan.
Add thyme, bay leaves, Herbes de Provence, stock, and lentils.
Increase heat to medium high to bring soup to a simmer.
Reduce heat to medium-low, and simmer, partially covered, until lentils are just tender, about 30 minutes.
Stir in spinach and vinegar; simmer 10 minutes more.
Garnish servings with crème fraiche, thyme, and cooked bacon.