May 1: Le Fête du Muguet
On the first of May, 1561, King Charles IX of France received some muguet (lily-of-the-valley) for luck, and began the tradition of handing out these flowers to those in his court. In 1889, May 1st was adopted as Labour Day in France, and in the early 1900s, vendors began selling sprigs of lily-of-the-valley in the streets. The French government, usually strict about enforcing vending licenses, gives free reign to any to sell muguet on May Day—the caveat being that it must be wild and not cultivated (which is reserved only for florists). They are also allowed to sell them free of taxation.
No one works on this day (except for café owners), and one traditionally gives a little bouquet of muguet to friends to wish them happiness and good luck. The holiday surely stems in part from Le Fête de l’Ascension, long ago secularized by the state and made into a day of rest and general good will. Other Catholic feast days are still celebrated in France, like Toussaint (All Saints) and the Feast of the Assumption, but likewise have been turned into secular holidays by the state. Catholics, of course, attend Mass on the Solemnity of the Ascension, honoring the real reason behind the holiday: the triumph of Our Lord over death and sin and the perfect accomplishment of His mission in returning to the Father.