Welcomed by emails and note (with key). Host was working when I arrived. But all worked perfectly. It's an excellent, interesting neighborhood. The apartment is very nicely restored. There's a good coffee machine. Very nice host.
Yes, you will hear the "L" go by; but it didn't bother me at all. And the trains don't run very much late at night.
Note that you will be sleeping on a sofa bed, as described, so it's not the greatest mattress, but I slept well.
Overall, a very positive experience. Definitely stay there.