Where in France is the tour de France held?

Answer 1

It is held all over France and has a different route each year. The route now always finishes in Paris and passes through the Alps and the Pyrenees each year.
It is in France
Slightly different from year to year. You've gotta specify the year to get a decent answer.
France, but Stage 1 or Prolouge has started in various other cities/countries in Europe such as London and Monaco.
The route of the Tour de France changes every year. However, it is always designed so as to have its mountain stages held in both the Alps and the Pyrenees, and its last stage will always end on the Champs-Elysees in Paris.

Answer 2

France and Italy

Answer 3

France.