The St. Petersburg political opposition has applied to hold a September 15 "March of Millions," Rosbalt news portal said on Thursday.
The application is for several possible march routes in the central part of the city.
A parallel march will be held on on the same day in Moscow.
The first sanctioned March of Millions was held in Moscow on May 6, ending in clashes between police and protesters who had gathered at Bolotnaya Square, resulting in more than 400 arrests.
The opposition accused police of keeping demonstrators away from the march, while police accused the opposition of a deliberate provocations. Organizers said about 50,000 took part; police said around 8,000 participated.
Opposition and civic activists spent the rest of May holding "test strolls" through Moscow streets, occasionally resulting in arrests.
The second March of Millions was held on June 12, no arrests were made. The demonstrators marched from Pushkinskaya Square as far as Sakharov Avenue where a rally was held later. Some 18,000 took part in the march, and about 15,000 in the rally, according to police estimates. Organizers claimed a much bigger figure: between 50,000 and 100,000 demonstrators.