1. In a pot, heat the olive oil. Add the onion, garlic, celery, and bell pepper. Cook for 2 minutes.
2. Add the vegetable broth, smoked paprika, lemon zest, and tomatoes. Bring to a boil. Reduce heat and cook for 40 minutes. Season with salt and pepper.
3. In a deep pan, place the white wine and mussels. Cover and cook over low heat until the mussels open.
4. Transfer the mussels and their cooking juice to the soup.
5. Serve the soup very hot with the mussels and an olive oil sardine. Garnish with chives.