Hi Susan,
Thanks for using our website.
Yes, the number format is correct – spacing doesn’t make any difference as you will enter the number without spaces anyway.
Regarding your French – very likely the hotel reservation person speaks English so I wouldn’t worry about that. As for calling rates – generally using your cell to call internationally is pretty expensive, especially if you don’t have some special international plan activated. Using your landline is likely a better choice, although I would check rates first. The bigger US phone service providers charge high international rates. The lowest rates are charged by smaller companies (calling card providers, dial around services and the like). But then again, you will probably be on the phone for 1-2 minutes therefore your call will not cost a lot no matter what service you use.