Technically Twelfth night is the night of the 5th January which in the old world would be the start of the twelfth day since they counted sunset as the beginning of a new day. Celebrations would take place that evening and then decorations taken down the following morning ie the 6th which was twelfth day. Greenery would then be taken back outside the home to encourage new growth. Sadly we have lost a lot of the old traditions partly due to the fact that the 'festive' season is thrust upon us so early that by the time Christmas day arrives many are ready to stop celebrating rather than begin.
When I was in France 30 years ago we didn't go back to school until after Epiphany but the shops sold Galettes du roi which contained small crowns - probably banned now much like sixpences in Christmas puddings.