Both are very similar. Mini Lin was the original introduced : cotton and linen. It was very "dry" to the touch, and bags kept a great shape, but over time they wore out faster and were harder to keep clean. The original Mini Lin colors were Ebene and Dune. Idylle was launched around 2010 thru 2014 and also comprised of cotton but a substance called "polyamide" was added to make it more durable yet softer to the touch and with a bit of "sheen". I owned the mini lin pochette Cancun and a cles key pouch. Idylle also offered more color selections. (I found this info re: composition in my vintage Le Catalogues that describe the materials).