6. a small strip of coloured cloth signifying membership of an order or award of military decoration, prize, or other distinction. 7. a small, usually looped, strip of coloured cloth worn to signify support for a charity or cause: a red AIDS ribbon.
The books burned were Jewish, Marxist, Bolshevik, or other disreputable or non-German books. These included the works of Heinrich Heine, Sigmund Freud, Thomas Mann, Erich Maria Remarque, Albert Einstein, Walter Benjamin, Karl Marx, Jack London and Margaret Sanger.
You can probably avoid black marks on the wall by burning (good-quality) candles on a coffee table, FAAAAR away from the walls. You might also consider an alternate light source, such as a salt lamp (which use either small lightbulbs or small candles) which would still be soothing but perhaps not so problematic.