TOKYO — Japanese newspaper publishers Nikkei Inc. and The Asahi Shimbun Co. jointly filed a lawsuit on Tuesday against U.S. artificial-intelligence start-up Perplexity AI Inc., accusing the company of infringing their copyrights by copying and storing articles without permission. The complaint, lodged with the Tokyo District Court, seeks an injunction halting further use of the newspapers’ content and 4.4 billion yen ($30 million) in damages — 2.2 billion yen from each publisher. According to the filing, Perplexity allegedly bypassed technical safeguards to access the companies’ servers beginning no later than June 2024, then generated and distributed summaries that misquoted or misstated facts while citing the papers as sources. The publishers argue that the practice constitutes large-scale “free riding” on their journalism and undermines their credibility. The action follows a similar complaint lodged this month by Yomiuri Shimbun Holdings and adds to a growing wave of legal challenges worldwide over the use of copyrighted material to train and power generative-AI services. Perplexity, founded in 2022, has not publicly responded to the Japanese suit. The case could clarify how Japan’s Copyright Act applies to AI-driven search products as media organisations seek compensation for the use of their work.