In recession the Parisian rents increase continually (6)
I believe the answer is:
spiral
'increase continually' is the definition.
(as in spiralling debts)
'in recession the parisian rents' is the wordplay.
'in recession' says the letters should be written backwards (letters recede or go back).
'the parisian' becomes 'la' (French for the).
'rents' becomes 'rips' ('rip' can be a synonym of 'rent').
'la'+'rips'='larips'
'larips' backwards is 'SPIRAL'.
(Other definitions for spiral that I've seen before include "Shape of a coiled spring" , "Corkscrew shape (6)." , "Whorl" , "Sir, pal winds in continuous loops" , "Scandalise" .)