A3 712 then QR 3670 at Barcelona
Athens → Barcelona → Nantes
Timetable, Barcelona time
18:45A3 712 from Athens at the gate
07:40QR 3670 to Nantes leaves the gate
12 h 55 apart on the timetable, overnight
QR 3670 leaves 12 h 55 after A3 712 arrives on the timetable: more than half a day, so not a connection we count.