Renault SA's mishandling of an espionage investigation has weakened Chief Executive Officer Carlos Ghosn in a tussle with the French state, its largest shareholder, over the carmaker's future, several sources said.

Fallout from the spying affair, in which Renault says it may have been hoaxed into firing three executives, will make it harder to win government support for changes to its alliance with Nissan Motor Co., the sources said.

Renault wants to reduce its Nissan stake and allow the carmaker to vote as a Renault shareholder, they said, declining to be named because the matter is confidential.