French phrase
Quelle unité doit-on utiliser pour ~ ?
Meaning
Which unit should be used for ___?
When to use it
It asks which unit or currency should be used. The phrasing is polite and works well when confirming how a charge or amount should be expressed.
Example dialogue
Quelle unité doit-on utiliser pour les frais de scolarité ?
Which unit should be used for tuition fees?
En général, on indique les montants en euros.
In general, amounts are given in euros.