WASHINGTON (AP) — The D.C. Taxicab Commission says it’s illegal for the popular taxi and sedan service Uber to charge an automatic 20 percent tip on rides booked through its app or website.

The Washington Examiner reports that D.C. taxi regulator Ron Linton told taxi drivers in February that he asked Uber to stop charging automatic tips. Linton wrote in an e-mail Friday that he had been assured by Uber’s attorney that it would comply with the city’s taxi regulations.

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But Uber says it does not believe the automatic tip is illegal. Uber General Manager Rachel Holt says the tips go entirely to the driver and that customers know about the policy.

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The taxicab commission says it won’t be able to do anything about the tips until a rider complains about them.

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