Veste Croisée #2492
The pattern is a house pattern 2492 for La Droguerie, Paris, France and is available for free with the purchase of the yarn, although it is in French. It calls for using the house yarns of a 3-ply light fingering weight yarn alpaca and a 2-ply mohair (70%)/polyamid (30%) combined as one yarn and adding up to 460 grams for a small and 510 grams for a medium/large, and perhaps one could substitute a 5-ply yarn adding up to the same weight and gauge.
It should fit loosely and comfortably. It does not button as a traditional cardigan would, but has an asymmetrical closure across the front with a button attached on the left shoulder. The collar is loose and relaxed in appearance, leading to front panels that drape on bust and hang well below the bottom edge of the cardigan back.