Pour a shallow layer of vegetable broth into a soup pot and heat. Sauté onion and garlic over high heat until onions start to become translucent, about 2 minutes.
Add carrots, celery, and remaining broth and bring to a boil. Once boiling, reduce to medium, cover, and keep cooking until carrots are softer but still firm, about 5 minutes.
Add half of the thyme and parsley, followed by the tomato and tomato paste, stirring to combine.
Continue to cook until carrots are fork tender and soft, but not mushy or not falling apart, about 4 more minutes.
Stir in beans (with liquid) until well combined and add the remaining thyme and parsley. Reduce heat to low and cook for another minute or two, just to warm the beans up a bit.
Stir and taste, adding salt and black pepper if desired. Ladle into bowls and garnish with a thyme sprig.