It is a tradition in France that on May 1st, May Day - French Labor Day/Fête du Travail people will pick wild Lily of the Valley Muguets in French).
Also, it is very common to see roadside stands or people in front of supermarkets selling Lilies of the Valley, often to gather funds for an organization.
Lily of the Valley is a small plant that gives off a very nice smell. The tradition is: you go out and gather the Lilies of the Valley, enjoy the spring weather and get a little exercise. Then, when you have collected your Lilies of the Valley, you put them in a vase in your home to bring their perfume home.