Whisk together mustard, salt, shallots, parsley, and 4 1/2 teaspoons vinegar in a large bowl.
Add 3 tablespoons oil in a slow stream, whisking until emulsified.
Heat remaining tablespoon oil in a 12-inch skillet over high heat and brown bacon with pepper, stirring, 1 to 2 minutes.
Fill a deep 10-inch skillet with 1 1/2 inches of water and 1 teaspoon vinegar and bring to a simmer. Break 1 egg into a cup, then slide into water. Repeat with remaining 3 eggs, spacing them evenly. Poach at a bare simmer until whites are firm but yolks are still runny, 2 to 3 minutes.
Transfer eggs to paper towels and season with salt and pepper.
Toss frisée with dressing.
Serve topped with bacon and eggs.
The egg yolks are not fully cooked, which may be of concern if salmonella is a problem in your area.