Cut the sausage into slices. Heat 1 tablespoon of oil and fry the sausage for approx. 5 minutes, turning it over. Pour beans into a sieve, rinse if necessary. Add to sausage and heat. Wash the thyme, shake dry, remove leaves except for some garnish from the stalks and add.
Peel and dice the onion and garlic. Heat 1 tablespoon of oil and fry the onion and garlic until transparent. Add tomatoes to the onion-garlic mixture, bring to the boil and season with salt, pepper and sugar.
Arrange beans and sausage with the tomato sauce on plates and garnish with thyme.