Steps to renovate uneven oak tiled Parquetry on cement?
There may be a better ways of doing this but I could see either laying down backer board of the thickness needed to make the parquetry the same height as the existing. You'll want to lay the backer board in a bed of thinset and a few concrete screws. Or depending on the size of area you may be able to get away with pouring self-leveling concrete mortar to the desire thickness and then the parquetry. The existing concrete will need some prep to get it to adhere well.