Why was the colour yellow chosen for the jersey introduced to mark the current leader of Tour de France in 1919?

Explanation

The yellow jersey (in French: Maillot Jaune) is worn by the current leader of the Tour de France. The jersey was introduced in the middle of the race in 1919. The journalists from the paper L'Auto (now L'Equipe) wanted to make it easier to spot the frontrunner, and thus had the jersey introduced. It became yellow, because the main sponsor, L'Auto, printed their newspaper on yellow paper. The Tour de France was the first competition to introduce a yellow jersey.