An estimated 100 Chinese volunteers fought in the Spanish Civil War for the Republic, though only one person is thought to have come directly from China to fight, as the rest already found themselves in Europe working. A book has just been translated into Spanish on them: “Los brigadistas chinos en la guerra civil. La llamada de España (1936-1939)”. More here
And here: El soldado Xie Weijin contra Franco
Chinese volunteers imprisoned together with other brigaders, I think in France.