Google's Gmail privacy has been under attack in recent weeks by a Microsoft-backed campaign called Scroogled, but Simpson said his group's complaint is independent of those efforts.
The FTC complaint is a continuation of Consumer Watchdog's past efforts on Google privacy, he said in an email. "We see this as the fifth privacy violation in three years," Simpson said.
Apps sold on Google Play can deal with sensitive personal subjects, including health information and sexual activity, Simpson said in his complaint.
Simpson disputed Google's assertions that it was sharing information necessary for the app transaction. "Checking the relevant privacy polices, we found no indication that Google would share this information with apps developers," he said. "Google Wallet talks about sharing data necessary for the transaction, but this information is NOT necessary for the transaction."
Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is firstname.lastname@example.org.