Narrow interior door for the attic - ideas?

Hello, a door directly in front of/at the stairs would be neither allowed nor sensible (dangerous). Alternative: build a drywall partition parallel to the existing wall, then there is space for a normal door. But a curtain made of heavy fabric is, as already mentioned, a good substitute (we had it for years as a temporary solution in the "Kaminzimmer") ... it also helps quite a lot. We had a lead tape sewn into the hem at the bottom so that it lays nicely on the floor.