How it differs from a transfer
A transfer buys a journey. Hourly hire buys time. In the first case the price depends on where you end up. In the second it does not depend on it at all, and the destination field disappears from the booking form altogether.
The practical effect is simple: at 9 am you no longer need to know where you will be at 3 pm. This is the only format that tolerates a loose plan, which is why it suits days of back-to-back meetings, property viewings, sales rounds, and days where you are accompanying someone rather than dropping them off.
What four hours really buys
Four hours is the floor, and it is not a commercial one. Below four hours, holding a car costs more than simply pricing two separate journeys. Along the coast, four hours comfortably covers three or four stops spread over twenty kilometres or so.
Past that, the maths stays linear: every additional hour is charged at the same hourly rate. No tiers, no hidden discount, no day rate that quietly absorbs an overrun. A flat night supplement applies if the pickup falls between 11 pm and 7 am, Paris time.
The plan is settled on the move
Your chauffeur is not working from a frozen itinerary. He knows the windows that matter: when the A8 tightens westbound, when the lower corniche beats the middle one, which streets flip to pedestrian use in the late afternoon. Those calls are made during the day, without anyone asking you to arbitrate.
That is also what separates a booked day from a string of on-demand rides. Your belongings stay in the car between stops, and nothing starts from scratch each time you get back in.
What turns into a quote
Three cases leave the hourly rate. Travel outside the included 50 km radius. Luggage beyond the capacity of the car, which is two large cases in a saloon and six in a van. A request for an exceptional vehicle, which never carries a displayed price.
In all three the booking engine does not produce a figure: it opens a quote request instead, with an answer promised within the hour. That is a deliberate choice. A price shown and then corrected after the journey is worth less than a price given an hour later and held.
Three places the car will not go
A day out here runs into closed perimeters quickly, and it is better to know beforehand. The Rock of Monaco is closed by municipal order to any vehicle not registered in the Principality or in the Alpes-Maritimes: the restriction is administrative, so a smaller car does not solve it.
In Cannes, access to the permanent pedestrian zones is capped at thirty minutes, parking is forbidden outright, and only a short stop for loading is allowed. In Vence, the old-town bollards open on a magnetic badge or through an intercom staffed around the clock, and the Porte d’Orient opens only on Tuesdays and Fridays across two short windows. In each case the drop-off is planned ahead rather than improvised at the barrier.