The District of Columbia filed an antitrust lawsuit against online retailing giant Amazon today, accusing the Seattle-based company of using its monopoly power to harm consumers. Amazon is the world’s largest online retail platform. As of May 25, the company had a market capitalization of $1.63 trillion, and according to the Wall Street Journal, was close to completing a deal to acquire MGM, the Hollywood movie-making studio. “Amazon has used its dominant position in the online retail market to win at all costs. It maximizes its profits at the expense of third-party sellers and consumers, while harming competition, stifling innovation, and illegally tilting the playing field in its favor,” District of Columbia Attorney General Karl Racine, a Democrat, said in a press release. “We filed this antitrust lawsuit to put an end to Amazon’s illegal control of prices across the online retail market. We need a fair online marketplace that expands …