Very loud song across a French amusement park
I believe the answer is:
fun fair
'amusement park' is the definition.
(I've seen this before)
'very loud song across a french' is the subsidiary indication.
'very loud' becomes 'ff'.
'song' becomes 'air' (I've seen this in other clues).
'across' indicates putting letters inside.
'a french' becomes 'un' ('a' transated into the French language).
'ff'+'air'='ffair'
'ffair' going around 'un' is 'funfair'.
(Other definitions for fun fair that I've seen before include "Travelling show with rides, games and much else" , "Travelling entertainment" , "Amusement ground" , "open-air entertainment" , "Travelling attraction" .)