Heat the oil in a heavy stockpot over medium-high heat.
Add the celery, onion, and red pepper, and sauté for 6 to 8 minutes until tender.
Stir in the garlic, tomato paste, and seasonings, then cook for 1 minute.
Add the sausage and tomatoes and cook for 5 minutes.
Stir in the broth, then bring to a simmer and cook, uncovered, for 20 minutes.
Adjust seasoning to taste then add the shrimp.
Simmer until just cooked through, about 3 to 4 minutes.
Spoon into bowls and serve with fresh cilantro.