We evaluate the evolution of productivity gains from Chinese cities over time, from 2002 to 2013. In 2002, rural migrants were exerting a strong positive externality on natives' earnings, which were also higher when access to foreign markets through access to sea was higher. In 2007 and then further in 2013, city size (employment density but also land area) has become the crucial determinant of productivity whereas market access, internal or external, plays no direct role. Rural migrants still enhance natives' earnings, though the effect is more than hal f lower than in 2002. Urban gains, and their evolution over time, are very similar on total and per hour earnings. Skilled workers and females seem to gain slightly more from cities than unskilled workers and males.