Los Angeles County prosecutors say Juarez, 59, received that donation from the owner of Gold's Gym in Hawthorne after he was elected to the Hawthorne City Council.
Juarez allegedly accepted the cash and deposited it into his private account without reporting it on two campaign statements filed in January 2010 and March 2011.
He has pleaded not guilty to the charge.
Hawthorne's last mayor, Larry Guidi, pleaded guilty to felony grand theft for stealing a commercial food mixer from the Hawthorne School District.
Juarez is due for a pretrial hearing Dec. 10. If convicted, he faces up to five years in state prison.
The Associated Press contributed to this report.