Julienne the carrots finely.
Mix the julienned carrots with olive oil, lemon juice, salt, and pepper to make carrot râpé.
Pan-fry the Bockwurst sausages.
Cut the baguette or ciabatta bread in half and hollow out the inside slightly.
Spread mustard sauce on the bread.
Place the Bockwurst sausages, carrot râpé, and lettuce on the bread.
Optionally, add arugula or pickles to finish the sandwich.