'Muguets' are lilies of the valley.
The stop takes its name from Rue des Muguets. In France, as in Switzerland and Belgium, these white spring flowers are traditionally given on 1 May as a lucky charm, because they bloom around that date. In the early 20th century it became a tradition in France for labour organisations and private people to sell them on Labour Day, 1 May, without paying sales tax that day.