You are allowed to do so in CL. The Bayern fan next to me just said it will cost them €21m to get Coman and he is on a 2yr loan.
My understanding was that UEFA doesn't allow clauses that prevent loanees from being played against their parent club, or at least declares any such clause to be unenforceable.
He looks like some player. Lightning quick, direct, excellent delivery, he looks like the successor to Robben.
And now he's been picked in the latest French squad https://twitter.com/UEFAcom_fr No place for Morgan though.....