Old French city waiting in readiness (2,3)
I believe the answer is:
on ice
'waiting in readiness' is the definition.
(on ice means ready or prepared)
'old french city' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'french city' becomes 'Nice' (Nice is a French city).
'o'+'nice'='ON ICE'
(Other definitions for on ice that I've seen before include "Predatory insect" , "held back?" , "Awaiting decision" , "Waiting" , "not to be furthered?" .)