Upvote:1
The FAQ has a whole section on regular (non-web) check-in and mentions βcheck-in deskβ without hinting at extra costs so it seems pretty safe to conclude that checking in at the airport is possible (I have not done it myself).
Also, Can I choose my seat when I check in? implies that choosing a seat should not cost you anything:
You can check in and reserve a seat free of charge by checking in online or using a check-in kiosk at the airport.
(Selecting an exit row with extra leg room does cost extra.)
Upvote:1
I flew with Germanwings last year and checked in at the airport on both legs. No extra charge.