According to Schengen Visa rules if applying for tourist visas:
“you should apply where you would be staying maximum number of days.
If you are spending equal number of days in Schengen countries, then
you will have to apply where you will be entering first."
Which Embassy to apply for a Schengen visa? The number of days is the same for Netherlands and Switzerland?
1 Germany (6-8 Sept)
2 Netherlands(8-11 Sept)
3 Switzerland(11-14 Sept)
With the provided itinerary, it really looks simple to apply for Germany because of equal number of days in each Schengen countries. However when we reach Schengen Embassy/Consulate or VFS (Visa Facilitation Center), they normally start counting with provided hotel/accommodation booking by nights for each member Schengen member states.
1 Germany (6-7) 2 nights
2 Netherlands (8-10) 3 nights
3 Switzerland (11-13) 3 nights
So obviously we cannot apply to Germany because applicant is just staying there for 2 nights. However there is equal number of nights stay in between Netherlands and Switzerland, therefore applicant has to apply for Netherlands because he will be entering Netherlands before Switzerland.
Personally with my own experience with German and Italian Consulates I noticed the same procedure whenever I applied for a Schengen visa, I still need to justify my answer from Schengen Embassy/Consulate.
The answer below is provided by Embassy of Switzerland (Schengen