Clean and wash the radishes, dab dry and cut into thin slices. Wash sprouts and salad and drain well. Peel garlic and press it through a garlic press.
Mix mayonnaise and garlic and season with salt and pepper. Spread slices of toast with some garlic mayonnaise and cover one slice with lettuce, radishes, brie and sprouts. Add the remaining mayonnaise and cover with the second slice.
Cut the sandwich diagonally.