A Volgograd district court rejected on Tuesday a suit by former Mayor Roman Grebennikov, who contested his removal from the job, Interfax reported.
The court is to announce its reasoning behind the verdict within five days. A representative for Grebennikov nevertheless promised on Tuesday to appeal the ruling.
He also said the mayor was punished for opposing the plans to install a city manager in Volgograd, infringing on the residents' rights to elect their governor.
Grebennikov was sacked last month by regional Governor Anatoly Brovko for unspecified violations of human rights and ignoring court rulings. He was purged from the ruling United Russia party soon after.