@saab,
It would be even more interesting to know the (registration) nationality of that plane: all foreign air traffic was forbidden in Switzerland since 1939, and the Swiss air branch of the army shot down every unidentified plane.
An even more serious problem would have occurred when entering the Vichy-France airspace, controlled by the German military...
As a map, you could use a topographic one
You can enlarge the view on the
>original website<
An aeronautical chart would be much better, though. But I have some doubts that you can find one of that period easily.