Yes Ben78 that's right. The taxation is lower than the other European country. You can have an idea here
https://www.lohncomputer.ch/en/.
If you are a commuting pilot, you can deduce a lot of money, and in this case you won't pay any tax before reaching the left hand side of the cockpit.
Switzerland has a lot of conventions concerning double taxation with many European countries, most likely when company is based in Geneva. If you live in France and work in Geneva, you won't pay any tax in France.
I think it only depends where you live. E.g. you are based in Hungary, you pay tax in CH and social contributions in HUG.
Ben78 you mentionned that FO earn 14-15K sector pay ? Are you sure of that ?
I heard that sector pay is only once you are SFO !