The Yunnan–Indochina railway, built by France across the China–Vietnam border between 1898–1910, never realized the expansionist dreams of French colonialists in Indochina and therefore has been studied as a failure of French imperialism. Taking a labor perspective, this article examines the labor conflicts along the Yunnan railway against the backdrop of the emergence of a global labor market where different colonial powers competed for cheap Chinese labor after the emancipation of black slaves. At the time of the railway's construction, access to cheap labor was so central to colonial competition that the metropolitan, colonial, and business agents of the French empire found themselves in a dire conflict over labor shortages in Yunnan. To the extent that France failed to restrain the railway company agents from abusing the labor force, other European colonial powers used worker misery to dispute French claims to conducting a “civilizing mission.” At the same time, both Qing imperial officials and Chinese nationalists advanced their arguments for national sovereignty in the name of protecting their national subjects, i.e., the railway workers. As a result, French recruiters had to reconsider the terms of Chinese coolie employment, increase wages, improve worker contracts, and invest in welfare systems. In sum, worker resistance during the construction of the Yunnan railway not only delayed the railway's completion and diminished French colonial prestige in the region but also empowered the workers, giving them leverage to increase the value of their labor in a market extending beyond Chinese national borders.