Seems the KE-OK partnership is developing: Korean Air / CSA Czech Airlines Expands Codeshare Service from late-March 2013

KE will codeshare on OK flights from PRG to: ARN; CDG, NCE; FCO, MXP; MUC, TXL, STR; and ZRH.

As PRG is further east than AMS or CDG, it should mean KE can offer slightly faster routings via PRG, as there's no need to double-back from locations in Germany, Italy, etc. Also, I get the impression that PRG is a fairly compact and uncrowded airport, so it may be quicker (or at least easier) to transfer through than CDG or AMS.

OK will codeshare on KE flights to BKK, DAD, DPS, FUK, GUM, HAN, SGN, CGK, ROR, BKI, KUL, NGO, KIJ, OKJ, KIX, CTS and NRT.