The head of France's Green party on Saturday threatened to withdraw support for the Socialist government unless President Francois Hollande made a clearer commitment to protect the environment, reports Reuters.
The Greens have two ministers in the cabinet, at the housing and development ministries.
While the government does not rely on Green support to pass legislation, its loss would leave little room for dissent among the Socialists and their left-wing allies to get laws through.
Out of 577 seats in the lower house of parliament, the Socialists and their allies hold 292, while the Greens have 18.
The Green party has accused the government of dragging its feet on environmental policy after Environment Minister Philippe Martin put off plans for France's transition towards less carbon-intensive energy sources until next year.
Read more of this report from Reuters.