Step by step

Boil the French beans in salted water for two or three minutes

If you don't want to use tomato passata, you could instead make a sauce with fresh cherry tomatoes. You might also garnish your sauce with some toasted breadcrumbs and a balsamic vinegar glaze, or with a little grated ricotta.
Long, green beans are often prepared, in the rest of Italy, as part of a stew with tomatoes, but not with pasta. The combination of pasta with a tomato and bean sauce makes for a quick and healthy dish.