Orphee's obsession with deciphering hidden messages contained in random radio noise is a direct nod to the coded messages that the BBC concealed in their wartime transmissions for the French Resistance.
The opening scenes set in the Cafe des Poetes were originally set to be filmed with regular extras. However, Cocteau found them to be too self-conscious and artificial so they were all dismissed. Instead, real bohemians from Paris' real café culture were drafted in. These proved to be so natural and relaxed with the café setting, they actually stayed on for two extra days after filming had finished, just hanging out in the cafés that the film crew had been using.