Going up old street in France for currency (4)
I believe the answer is:
euro
'currency' is the definition.
(I've seen this before)
'going up old street in france' is the wordplay.
'going up' says the letters should be written backwards.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'street in france' becomes 'rue'.
'o'+'rue'='orue'
'orue' in reverse letter order is 'EURO'.
'for' acts as a link.
(Other definitions for euro that I've seen before include "Bread" , "Spanish currency unit" , "Basic monetary unit for 19 countries" , "Currency since 2002" , "Multi-national currency" .)