I have been being haunted the theme music from 'Versailles' which I thoroughly enjoyed but the music is a particular mind ear worm . . . . . . it is apparently by M83 (although others have mentioned somebody called  Eduardo Noya who is the series music composer and has 'used' this piece by the band)  and is noted as 'Outro' it is used as the theme intro music to Versailles (Now and Forever I'm Your King) . . . enjoy

Give credit where credit is due . . . . . . . there is only a briefest passing mention of this on their Wikipedia page!