A pair of Frenchmen love contents of magazine (4)
I believe the answer is:
ammo
'contents of magazine' is the definition.
(I've seen this before)
'a pair of frenchmen love' is the wordplay.
'pair of frenchmen' becomes 'MM' (two M's - M is short for Monsieur).
'love' becomes 'o' (love means zero in tennis).
'a'+'mm'+'o'='AMMO'
(Other definitions for ammo that I've seen before include "What's fired from a gun (abbr)" , "Slugs perhaps" , "essential supplies for soldiers" , "Bullets, say, in short" , "explosives, perhaps" .)