Well isnt Basle actually itself IN 3 countries, France, Switzerland and Germany?
No, the airport itself is in France and Switzerland.
The entrance is entirely in France, however there is a French passport control area and a Swiss passport control area.
A good chunk of the tarmac and part of the runway are in Switzerland however, with the remaining being in France.
However, if you are looking at total area, the airport is mostly in France by a little bit.
Here is a map, although it isn't very good and doesn't show a lot of the airport:
The left side of the green line is Switzerland while the other side is France.
If you want to go to Switzerland, you go through the Swiss passport control.
If you want to go to France or Germany, you go through the French passport control area since both Germany and France are European Union members.
The German border is pretty close and can be accessed from the French side.
Technically the airport serves Basel (or Basle as the French say) in Switzerland, Mulhouse in France, and Freiburg in Germany.
Even though the airport itself is built only on Swiss and French land.
"Generosity is giving more than you can, and pride is taking less than you need." - Khalil Gibran