The 27-year-old has fallen behind Alphonse Areola in PSG’s goalkeeping pecking order and he’s made just one Ligue 1 appearance so far this season.
A switch to the Premier League may be attractive to the Germany international, who will want regular action in the lead-up to next summer’s World Cup, and joining Palace may well be an option.
Eagles boss Roy Hodgson is thought to be looking for a new No.1 with Wayne Hennessey and Julian Speroni, who have shared the role in recent matches, both failing to convince the former England boss at Selhurst Park.
Trapp moved to PSG from Eintracht Frankfurt in summer 2015 and he’s made 78 appearances, keeping an impressive 44 clean sheets along the way.
Paris Saint-Germain are reportedly ready to launch a summer raid for Chelsea left-back Marcos Alonso.
Terriers midfielder Phillip Billing has spoken about the whirlwind nature of his move from Denmark to Huddersfield as a teenager.