So called 'cherry' tomatoes are very hardy and keep growing for several years as a bush - no spectacular big fruit but nice for snacking on or cut in half in a salad. Beware of biting them whole as they can explode and squirt seeds and juice between closed lips DAMHIK. They are slightly frost hardy but I don't know about German winters. Ditto 'Passionfruit' - they will grow all over the place then the vine dies back in winter - I think they will grow back from the root stock if the roots don't get too badly frozen - your local wild life will soon learn to help themselves to even green passionfruit.
This kind is usually called "Cocktailtomaten" in Germany, and yes, they are very nice. Eating them whole is a skill well worth learning - but at least you can do that, I find it much harder to eat a regular-sized tomato without making a mess!
German winters, though, will reliably kill off all tomatoes, passionfruit, peppers, chilis, or Morning Glories. We're getting temperatures below zero even during the very warm winters, and around zero for long enough so tomatoes don't survive.
The passionfruit will thus live in a pot and stay in the wintergarden during the winter. If, that is, the seeds do sprout... I'll know more in a few weeks' time.