well, still can't makes sense of this.
I keep trying but it's just not working somehow. Just departed from LFQQ with one AI parked. So far so good, it's a small airport. Now I reached my cruising altitude and I haven't seen any other aircraft on TCAS so far, while I even overflew LFPG. It's just empty out there (compared to FSLTL, where I always see one or two aircraft once in a while).
I'm heading for LEBL, but I kinda already expecting to just arrive at an empty airport.... we'll see.
No Idea what else I can try at this point.
Edit: okay, saw no traffic in the air or during approach BUT barcelona was populated with parked and moving planes :) fingers crossed...