One-Shoulder Long La Femme Formal Dress 31170A great find, this one shoulder long formal dress is simply delightful. In gleaming fabric from the asymmetrical neckline to the floor, this long designer dress by La Femme is an impressive choice for prom, galas, and other formal events. The a line evening gown has one thin shoulder strap that leads to the ruched back, and a pleated wide waistband that offers a long, lean look. The faux wrap long skirt opens in a side slit before flowing to the floor