French phrase
À partir de quand ~ est-il valable ?
Meaning
When is ___ valid from?
When to use it
Asks when something starts to be valid. It is polite and slightly formal, often used at a counter.
Example dialogue
À partir de quand le ticket de métro est-il valable ?
When is the subway ticket valid from?
Il est valable pendant 90 minutes.
It is valid for 90 minutes.