No, but Aleksandr Pushkin, Russia’s greatest poet, was.
Pushkin was 1/8 black, 7/8 white. Only one of his 8 great-grandparents was non-European. He was certainly mixed race, but it seems like a stretch to call him black. At least there’s actual legitimate evidence for that claim, though, as there is for Dumas, pere and fils, unlike for Beethoven.