Where Joan of Arc died is in question (2,5)
I believe the answer is:
at stake
This clue is a double definition.
'where joan of arc died' is the first definition.
(Joan of Arc was burned at the stake)
'in question' is the second definition.
(both can mean at issue or under discussion)
'is' acts as a link.
(Other definitions for at stake that I've seen before include "To be won or lost" , "Being risked or bet on" , "In danger; at issue" , "Being risked, depending on outcome of event" , "where many martyrs died" .)