Aim Far,
Bose-x is correct. If you're interested in an altiport check-out, however, there are plenty of mountain instructors who can help you and who are based at airfields you can fly yourself to safely.
Altiports like Courchevel are pretty tame, so there is no special need for local knowledge. At Courchevel, however, the landing fees in winter are extortionate, and this is a good reason for using locally based aircraft.
You need to be careful about getting mountain instruction in your own aircraft if it is complex or unusual in any way. Flying in a mountain environment is quite intimidating at first, and your brain can go into overload. If the instructor is relying on the student to handle the undercarriage, propeller, and other systems, things can go wrong. There was a well-known case of a British-registered Cessna 210 that landed gear up at an altiport due to the student being overwhelmed and the instructor being unfamiliar with the aircraft.