In a large pot, heat olive oil over medium-high heat. Add the beef stew meat and brown on all sides, about 5-7 minutes. Remove the beef and set aside.
In the same pot, add the diced onion and garlic. Sauté until the onion is translucent, about 3-4 minutes.
Add the carrots, celery, and potato to the pot. Cook for another 5 minutes, stirring occasionally.
Return the browned beef to the pot. Add the diced tomatoes, beef broth, green beans, thyme, oregano, bay leaves, salt, and pepper. Stir to combine.
Bring the soup to a boil, then reduce the heat to low. Cover and let it simmer for about 1.5 to 2 hours, or until the beef is tender.
Remove the bay leaves before serving. Garnish with fresh parsley.