Pro-Palestinian protesters demand that the institution condemn Israel's actions, in a protest that echoed similar demonstrations on US campuses
A few dozen activists gathered at Palace Square on Saturday afternoon, defying a ban to hold the rally.
Organisers had said they would stage one-man protests to demand freedom of association after city authorities turned down their request to hold a parade.
Russia passed a law in 2013 banning the spreading of gay "propaganda".
Last month, Russian police briefly detained British LGBT campaigner Peter Tatchell after he protested near the Kremlin in support of gay rights