Heat the olive oil in a skillet over medium heat. Add the beef cubes and brown them on all sides for about 5 minutes.
Sprinkle the flour over the beef and stir to coat evenly. Cook for 1 minute more.
Transfer the beef to the slow cooker. Add the chopped onion, sliced carrots, and cubed potatoes.
Pour in the beef broth. Stir in the mixed herbs, salt, and black pepper.
Cover and cook on low for 7 to 8 hours until the beef is tender and the vegetables are soft.
Stir the stew once before serving to check the consistency.