There may be intermittant snowing and raining, sun and wind, and absolutely freezing, but that's how you know Spring has arrived! Well, that and the daffodils. From March 21-23 (yes, that means tomorrow, Easter Sunday, is the last day), the square outside the Panthéon (5th) has been transformed into a daffodil garden (over 50,000 flowers) to benefit the Institut Curie's cancer research foundation: Un Jardin pour la Vie. You can buy the daffodils for €2 (€1 goes to the foundation). There will also be entertainment for children, live concerts, theatre performances, face painting, and free tours of the Musée Curie (around the corner at 1 rue Pierre et Marie Curie, 5th).
If you can't make it, or are huddling around your heater in this weather rather than going outside, then you can also support the cause by stopping by any Truffaut garden shop until the 30th of March, where you can buy your daffodils in a bouquet or as bulbs (50% of the proceeds go to the foundation).