To be quite honest, I'm not sure how the crèche de Noël came about. I do know that it had nothing to do with the officers who studied at St-Cyr. It's probably just one of those things that came about when the Legion was very active overseas. A kind of reminder of mainland France compared to the hardships of Algeria or Tonkin.
It's the same as the Christmas sketches. I can tell you that they were definitely not invented by ‘St-Cyrians’ as they were more often on the blunt end of them. For those who do not know, the Christmas sketches are when the legionnaires make fun of the cadre for what they have said, done or didn't do etc. Although it is meant to end there, some of the cadre can keep a grudge. One example I remember was in Djibouti on tournante with the REP. There was a Spanish Sgt with a real wicked accent. He was always bragging about how good he was.
The sketch (or part of it) performed by a legionnaire in his section:
“When I was a legionnaire, I was the most handsome, the fastest, the best in my section, that's why I was made up to corporal. When I was a corporal, I was the best corporal in the company, I knew everything, and I mean everything, that's why I was made up to sergeant. Now that I'm a sergeant, I've forgotten everything.â€
The legionnaire was given corvée for a week until it reached the adjudant company's ears.