Originally Posted by
tbaiyun
It has been disabled for quite a long time.
You can only add a "free" stopover in CDG or AMS on AF/KL itineraries, but this requires a call to FB. Be cautious that it may sometimes be very tricky as it may require both legs to have the same fare class or the stopover will become very costly.
Also, it will trigger a tax hike (can be a few hundred $ more).
This is awful. Every, and I mean every, full itinerary I've booked with AF/KL for the last 15 years has been multi-city.