Originally Posted by
caliform
Your best bet is to use ITA Matrix, which squarely lists the ticket fare class when browsing. KLM / AF themselves don't let you do this on their website, but perhaps their phone team can do this for you.
That's not true, until recently you were able to choose this via the KLM website, but since they are aligning classes with AF that option is for the moment not present anymore. Big annoyance as I used to use it to book flexible tickets.
According to the platinum line it should be back at around the 18th.
Believe on the AF site it is still possible though.