During the night I decided to leave Tunisia as soon as possible. That is, after breakfast I packed my stuff and cycled to the airport. There was a Lufthansa flight scheduled for the afternoon and I wanted to try and change my booking to that one today.
Lots of people around there. It turned out Tunisair employees were on strike and everyone going to Frankfurt was being booked on the Lufthansa machine. The Lufthansa office was still closed, though, with a long queue in front of it.
The one alternative flight was via Paris, cost around EUR 450, and they wouldn’t even take the bike.
To make a long story short, only minutes before departure I managed to get a seat on that Lufthansa plane! And it cost me only a minor re-booking fee.