The official website for The Settlers of Catan

Question about Artisans & Benefactors St. Agatha’s Chapel - Can I place a Pawnbroker on the Chapel?

Answer

Yes, but it makes no sense because you don't get anything in return: the star does not count as a resource. And to redeem the Chapel from the Pawnbroker's clutches, you would have to discard 1 gold and 1 star.

Note: The Pawnbroker is part of the them set "Trade & Change", which is part of the Catan Card Game – Expansion Set.