Select the French relish (6)
I believe the answer is:
pickle
'relish' is the definition.
(pickle is a kind of relish)
'select the french' is the wordplay.
'select' becomes 'pick' (picking is a kind of selecting**).
'the french' becomes 'le'.
'pick'+'le'='PICKLE'
(Other definitions for pickle that I've seen before include "Relish, difficult situation" , "Preserve; mess" , "tight spot" , "Chutney, relish, salsa etc" , "Solution for preserving food" .)