indoor or outdoor plant?

Fetthenne is the German name for Sedum itself. There is a Sedum hybridum which is a low growing hardy plant with yellow flowers.

If it looks like the Sedum in another question asked today ,What is this plant. then it is a hardy perennial and will lose its top growth but come up again next Spring.

Sedums are outdoor plants and are pretty hardy in spite of their succulent leaves. If it's like the one in the picture in the other question, then it's likely to be a Sedum spectabile hybrid. They will die down in winter but you'll see the new leaves coming up at ground level so the ground doesn't look too bare. Some of the low growing sedums such as Sedum rupestre or Sedum spathulifolium are evergreen although you will see a bit of colour change to the leaves in winter.

There are as many, if not more Sedums which are tender than hardy ones. It is (or was till they split it up) a large genus of plants. I could bore you with a list of tender ones, but I will refrain. :)

Ah - thanks for the correction! (The list might not bore me, but it could well have that effect on everyone else!)