On May 1st, in France, there is a tradition (the origin of which I don’t know) that men give a small stem of Lilly of the Valley to their female relatives and friends. It’s a rite of Spring, obviously. On that occasion and only on that occasion, private parties are allowed to sell the flowers in the street. Still, there are rules and regulations involved. You risk a significant fine if you violate Lilly-of-the-Valley sale rules.
May 1st, there is always a massive march for socialism in Paris. Would I make this up?