Filner is involved in a developing sex scandal as more women come forward and he brushes off calls to resign, even from Democratic Party chair Debbie Wassermann-Schulz.
Filner's office initially refused to accept the subpoena Thursday. The City Attorney's Office eventually caught up with Filner and served him personally, before the press conference in which he addressed called for due process in the investigation.
“The purpose of the deposition is to put him under oath and get his side of the story. That is what due process is," said City Attorney Jan Goldsmith.
The subpoena date coincides with Filner's self-proclaimed rehabilitation.
"On August 5, I will be entering a counseling clinic to undergo two weeks of intensive therapy,” Filner said, before being interrupted by a sound system failure. He returned to the microphone later to start over.
Filner said he will be at the clinic full-time, and will be briefed each morning and evening on city business. He stated his intention to return to his office on August 19.
Goldsmith said if the mayor is not deposed before August 9, he could be held in contempt of court and put in jail.
Filner is expected to answer allegations against him by former communications director Irene McCormack Jackson. Her attorney, Gloria Allred, filed the case against Filner and the city of San Diego on her behalf Monday.
The deposition will take place at the San Diego City Attorney's Office and will include city attorneys and Allred.
Since the lawsuit was filed, four more women have come forward saying Filner had made unwanted sexual advances toward them and touched them inappropriately. Seven women in total have accused Filner of sexual harassment.
San Diego County Democratic Party leaders voted to ask the embattled mayor to resign Thursday evening, just before Wasserman-Schulz announced the position of the Democratic National Committee.
Beyonce flaunts bikini body, Blue Ivy in vacation pics
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'