France is gradually converting to a grounded socket. The ground is created by a tine that protrudes from the wall socket and fits into a hole in your plug adapter. There is a photo here, under 'France':
https://www.toughleads.co.uk/pages/european-sockets
Some of the old two-prong adapters won't fit the new sockets because of the protruding ground.
Those clever-looking combo adapters sometimes have a fold-out piece of plastic that provides no ground protection at all.
I've had no trouble using a hair dryer that can be set for French current, but it only runs on low. It's easier to use the dryer which many hotels now provide. e-mail ahead if you want to be sure. If you carry several gizmos needing recharge, a short extension cord with a plug adapter can be useful.