This is a super cool Jean Paul Gaultier long black skirt. Its bottom cuts and folds make it look like both a pair of trousers and/or skirt. It's a very versatile piece - you can style it with a pair of heels and a fancy white top for an evening occasion or wear it with some sneakers for the day time. It features an elastic waist, making it very comfortable and suitable for a wider size range.
The size range is ITA 38 up to a 42 for a more fitted look.