The decision to ban Yabloko, the only party in Russia that opposes the war against Ukraine, was made on Monday by Russia's Supreme Court.
But this week, Yabloko leader Nikolai Rybakov claimed that the party will participate in the elections.
"We have a plan B," Rybakov said in a video on social media without giving any details.
The appeal filed by the party on Friday is expected to be heard on Monday. Rybakov told Reuters that he has no plans to leave Russia.
Another Russian opposition politician, Putin challenger Boris Nadezhdin, appeared in Paris last week after Russian authorities labeled him a foreign agent.
