Proceeds, if any, would go to The Maryland Theatre, he said.
Council members had varying reactions to Deming's idea.
Councilwoman Penny M. Nigh said she didn't mind it, but objects to his request to waive the city's open-container ban to allow beer and liquor.
"You can have a festival and you don't have to have alcohol," she said.
Alcohol is served at the annual Western Maryland Blues Fest and Augustoberfest, which are sponsored by the city, but Councilman Lewis C. Metzner said the city hasn't allowed liquor at events.
Councilwoman Alesia D. Parson-McBean asked questions about what Deming is trying to accomplish. She said it's "paramount" that he works with the city's economic development director on the festival, so it matches the city's idea of downtown revitalization.
Asked by Parson-McBean if the festival is meant to revitalize the downtown or promote a business, Deming replied, "My business is the revitalization of downtown."
Demcore has purchased several downtown properties, including the Rocky's New York Pizza building in Public Square and the Maryland Symphony Orchestra office and Barnwood Books building, both on South Potomac Street.
Demcore also owns and is renovating the former Schindel-Rohrer building at 28 S. Potomac St.
Councilman Kristin B. Aleshire said he thought it was unusual that the city would encourage activities at its parks, but debated whether to have an event downtown, where "it's needed no less."
Mayor Robert E. Bruchey II said the festival meshes with his interest in closing down Potomac Street occasionally for events.