In French service (in Italian, servizio alla francese) the waiter presents the serving dish to the guest, usually from the left, and the guest helps themselves with the serving cutlery. It is elegant and lets everyone choose how much to take.
The limit is speed: each guest serves themselves one at a time and with many guests the course goes cold. Not everyone is comfortable with serving cutlery, either. That is why it is used at small, formal dinners, with few tables and guests used to ceremony. There is also a historical meaning: old-style French service put all the courses on the table together, before Russian service, with courses one after another, became widespread.
What to ask
Service names are not the same in every manual. If a caterer offers French service, ask who holds the dish, who portions and where. The comparison is in the guide to types of banqueting service.
