I also received that email.
They charge 1184 € (not including transport/hotel) for a 2 days assessment in either 737 in Nuremberg or Prague. I call it BS, I don't know any airline/agency which charge that amount for an interview/assessment. And there is no mention for which airline they are hiring or contract condition, who knows it might even be for a p2f airline.
Seems way expensive just to be in their "database" without knowing for which airlines they work.