Heat olive oil in a large pot over medium heat.
Add the beef cubes and brown on all sides.
Remove the beef and set aside.
In the same pot, add chopped onion and sauté until translucent.
Stir in carrots and celery; cook for about 5 minutes.
Add minced garlic and cook for an additional minute.
Return the beef to the pot.
Pour in the beef broth and diced tomatoes.
Add green beans and dried thyme; season with salt and pepper.
Bring to a boil, then reduce heat and simmer for 45 minutes, until beef is tender.