They soothe us, boost our mood and help us open up our chakras. The therapeutic benefits of crystals are endless - stars such as Cara Delevingne, Victoria Beckham and Bella Hadid all use them. Just in time for the fall, Let's Play on the Moon, our favorite online store with a thousand and one crystals has opened its ephemeral hotspot in the heart of the Marais. The place is a hub of good vibes, where you can find agate, quartz and amethyst stones to give as gifts or treat yourself to.