French phrase
Combien serez-vous ?
Meaning
How many will you be?
When to use it
A polite question about how many people are in a party. Common for reservations and check-in.
Example dialogue
Bonjour, pour la réservation de ce soir, Combien serez-vous ?
Hello, for tonight's reservation, how many will you be?
Nous serons quatre.
There will be four of us.