Good old French bean salad

INGREDIENTS

• 4 handfuls French beans, stalk ends removed
• 2-3 heaped teaspoons French mustard, to taste
• 2 tablespoons good-quality white wine vinegar
• 4 tablespoons extra virgin olive oil
• sea salt
• freshly ground black pepper
• 1 medium shallot, peeled and finely chopped
• 1 tablespoon capers, optional
• ½ clove garlic, finely grated
• 1 small handful fresh chervil, optional