A short translation:

KLM is introducing an economy class with more legroom.
For PE members it is free; GE get 50% discount on the fee and SE get 25% discount. Full-fare Y passengers are also exempt from the fee.

The fee depends on the length of the flight. This new service is bookable from December, as all planes will be converted from September till December.

So instead of introducing a new class like AF, KLM has chosen just to increase the legroom & pitch [like UA E+].

Gajan