In Belgium (Flanders) and Netherlands a few preliminary (or indeed the main) presents are given out by Sinter Klaas and his assistants Zwarte Pieten (Black Petes) and it's a great excuse for a drink. It doesn't affect air travel these days. As far as I can read the legend, he used to ride a white horse in the sky, which might have led to some NOTAMs, but now he arrives by steamboat.
As for FR it would have affected Eindhoven, but I'm not sure about Charleroi -the legend was in ancient Flanders, which did include Lille (Rijsel) so it's not just a linguistic thing.
No doubt our Low Country friends can enlighten us further.
Saint Nicolas is on the 6th december and, in Belgium (both Wallonia and Flanders), the small children receive toys and candies that Saint Nicolas allegedly brings during the night, with his donkey, and deposits by the chimney. The "Père Fouettard" is just there to frighten the children that don't behave as they should.
This has no influence whatsoever on the ordinary life of adults, it's not a public holiday and everything works as usual, aviation included.