Last August, I arrived on LH
447 from DEN
and connected to SZG
in 65 minutes with a cat, and a stop for a coffee. However, I also, to use a turn of phrase, hauled ass to customs. Later that month, I did SZG
in 30 minutes from a hardstand (we were running late) but had to sprint through that tunnel. I made the connection. My fellow sprinter missed his to YVR
. On the return, again with about 30 minutes, I missed my connection and had to wait 4 hours for the next flight.
So, my point is that it's possible if risky. But given that FRA
is not the best place to spend more than an hour, I'd take the hour connection and not dally.