In a large stockpot over medium-high heat, heat the olive oil. Add the garlic, peeled and thinly sliced, and sauté until soft but not brown.
Add the tomatoes, sliced in half, and the shallot, thinly chopped. Cook, stirring occasionally, until the tomatoes start to release their juice, about two minutes.
Add the beans and stir to combine. Place the mussels on top and add the wine and one half of the lemon cut in rough pieces. Cover and cook for 5 to 6 minutes.
To serve, add a few more slices of lemon and sprinkle with minced parsley. Accompany with some slices of fresh country bread to soak up the delicious juices.