Combine diced tomato, mozzarella, basil leaves, vinegar, olive oil, salt and pepper in a bowl. Mix well. Cover and refrigerate for at least 30 minutes.
Preheat oven broiler. Place baguette slices on a baking sheet. Broil for 2 minutes or until golden brown. Rub garlic clove over the top of toasted bread.
Spoon chilled tomato mixture over the top of the bread. Serve.