Who in France tucks into wild oxen as a regular event? (7)
I believe the answer is:
equinox
'a regular event?' is the definition.
(eg the summer equinox)
'who in france tucks into wild oxen' is the wordplay.
'who in france' becomes 'qui' (French for 'who').
'tucks into' indicates putting letters inside.
'wild' is an anagram indicator.
'oxen' is an anagram of 'enox'.
'qui' going inside 'enox' is 'EQUINOX'.
'as' acts as a link.
(Other definitions for equinox that I've seen before include "Day with 12 hours of light" , "Biannual event" , "March happening" , "it occurs twice a year" , "Feature of spring" .)