From the French as it should be (5,2,4)
I believe the answer is:
comme il faut
'should be' is the definition.
I can't judge whether this defines the answer.
'from the french as it' is the wordplay.
I cannot really understand how this works, but
'from' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'french' could be 'f' and 'f' is found in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for comme il faut that I've seen is " Correct in etiquette (French)".)