Rinse the capers under cold running water, rinse and pat dry with a paper towel.
In a small bowl, whisk together the remaining 2 tablespoons of olive oil, the Dijon mustard, and vinegar. Add the tomatoes and mix well. Set aside.
Put 1 tablespoon of olive oil in a medium-size skillet over medium heat. When hot add capers, shallots and fry for 1 minute, gently shaking the pan. Add the tomatoes and the olives. Season with salt and pepper and cook for 2 – 3 minutes, just enough to warm.
Season generously the sea bass with salt and pepper
In a large straight skillet heat the remaining olive oil over medium heat. Once the oil is hot, add the fillets and pan-seared them for 5 to 6 minutes on each side, or until cooked through completely and the fish flakes easily.
Serve the fillets with the tomato relish and enjoy.
Optional: squeeze some lemon juice over the whole plate