Ok thanks for your answers.
Actually I had understood that Flygosh is just a middle man (in addition to Avia integrated), but I was wondering if they were only just trying to get 200€ per person or if you have a chance to get the position when you go to the interview.
I now understand that the answer is yes... So basically it's not a scam, it's just a "standard" P2F offer.
Just to continue on that topic, is Garuda Citilink aware of that? I mean, do they think that these pilots are just normal contractors? Because, on this offer the name of the airline is clearly associated with P2F...