German here. It was common a few decades ago but there have been a lot of safety campaigns and these days it's unthinkable for most young adults and exceedingly rare.
Only exception I can think of is the German president, who had real candles on his tree during the traditional Christmas address. But I wouldn't be too surprised if there were fire safety officers keeping an eye on the tree in case it spontaneously decides to do something dangerous.
I would be surprised if live candles on Christmas trees don't void your insurance in Germany, actually.
I'm in Sweden. Haven't seen a family with real candles in their tree since my grandma occasionally used them 30+ years ago, and even the they where only lit for a short while on christmas eve and electric lights where used all other times. Everybody I know here has electric lights, but often long strands of small bulbs, rather than the fake candle variety.
