An estimate: Say 1000 resorts with on average 50 pistes make up 50.000 pistes.
No, you cannot ski in Paris, France.
5 runs
Vars ski resort is very highly ranked making it one of the best ski resorts in France. They have many amenities that make them so highly recommended by many skiing enthusiasts.
A good place to start would be Maximumski. They are one of the leading online agencies to help you find the best ski chalets in many ski resorts in France.
600 km
Yes, Europe has the most ski runs in the world.
None. But there are are quite many ski resort covering two countries: France/Italy, France/Switzerland, France/Andorra, Switzerland/Italy, Switzerland/Austria, Italy/Slovenia and Austria/Germany.
Here you will find a list of some of the major ski resorts in France: http://en.wikipedia.org/wiki/Category:Ski_areas_and_resorts_in_France
Bridger Bowl Ski Area is in Bozeman, Montana and it is accessed by a well maintained road. It has seventy one ski trails of varying degrees of difficulty.
The largest ski resort in France and in the world is Les 3 Vallées with 600 km of piste. For more information look at the question "What is the world's largest ski resort?"
The Risoul area of France is most commonly known for its mountains and snow conditions. There is a ski resort located there which is the most popular ski resort in France.
400 meters or 1,200 feet.