Air China books in R from Seoul to Europe, sample for Paris
Routing through CTU (cheapest, suggest a stop over for best food in Chengdu) & PEK (a bit higher)
Return possible from CDG & FRA (possible others)
Use ITA Matrix to search for all options with booking class R
Book directly with Air China for lowest price
Shows up on Kayak, Google usually has some pricing problems, if higher than just click on the link to Air China and play with multi stop