The Chicago Tribune filed a lawsuit against the AI search engine Perplexity on Thursday, alleging copyright infringement. The suit was filed in a federal court in New York.
According to the complaint, the Tribune’s lawyers contacted Perplexity in mid-October to ask if the AI search engine was using its content. Perplexity’s lawyers reportedly replied that it did not train its models with the Tribune’s work, but admitted it “may receive non-verbatim factual summaries.” The Tribune’s lawyers argue that Perplexity is in fact delivering Tribune content verbatim.
The newspaper’s legal team is specifically calling out Perplexity’s use of Retrieval Augmented Generation, or RAG. This is a method used to limit AI hallucinations by having the model rely only on verified data sources. The Tribune argues that Perplexity is using the newspaper’s content within these RAG systems, scraped without permission. Furthermore, the suit alleges that Perplexity’s Comet browser is bypassing the paper’s paywall to deliver detailed summaries of its articles.
The Chicago Tribune is one of seventeen news publications from MediaNews Group and Tribune Publishing that sued OpenAI and Microsoft over model training materials back in April. That lawsuit is still ongoing. Another nine publications from these publishers sued the model maker and its cloud provider in November as well.
While creators have filed many lawsuits against AI companies over the use of their work for model training, this case may test the legal liabilities surrounding the RAG method specifically.
Perplexity did not immediately respond to the Chicago Tribune’s story about the lawsuit, nor to a separate request for comment from TechCrunch. Perplexity is facing other similar legal challenges. Reddit filed a suit against the company in October. Dow Jones is also suing Perplexity. Last month, while Amazon did not file a lawsuit, it did send a cease and desist letter to Perplexity over AI browser shopping.