There are similar threads in most of the airline fora here (there's one in the UA forum with a few hundred posts, for instance).

I could definitely see an OTP-BER fare being one that AFKL doesn't feel like competing on, given that you're doubling back from CDG/AMS which means it will be overall longer than anything LH/OS/LO can offer and they're presumably not having trouble filling seats connecting with longhaul or the further reaches of western Europe.