(Reuters) -G-III Apparel Group Ltd said on Monday it has agreed to acquire the remaining 81% stake in Karl Lagerfeld for $210 million in cash, becoming the sole owner of the Parisian fashion brand. G-III, which owns brands including DKNY and Jessica Howard, will purchase the additional stake from a group of investors led by Fred Gehring of Amlon Capital BV. The apparel maker first acquired a stake in the brand in 2015. G-III said it expects the brand to represent more than $2 billion in retail sales. Launched in 1984 by German fashion designer Karl Lagerfeld – known for his pony-tailed hair an…