[Greece's far-left former finance minister Yanis Varoufakis (C) sits next to French Europe Ecologie Les Verts green party member Julien Bayou (L) as he joins the "Nuit Debout" (Up All Night) movement in Paris, on April 16, 2016]Former Greek finance minister Yanis Varoufakis on Saturday addressed opponents of the French government's workplace reforms at a protest in Paris, telling them the planned changes would "devalue labour".