Standard and Poor's (S&P) has cut France's credit rating to AA from AA+, reports the BBC.
The moves comes almost two years after the country lost its top-rated AAA status.
S&P said it downgraded France because high unemployment in the country was making it hard for the government to make important reforms which would boost growth,
The French government responded by saying that its debt rating was one of the safest in the eurozone.
S&P said it expected government debt to hit 86% of gross domestic product (GDP) in 2015 and unemployment to remain above 10% until 2016.
The country's Finance Minister, Pierre Moscovici, said S&P had made "critical and inexact judgements".
He said in a statement: "During the last 18 months the government has implemented major reforms aimed at improving the French economic situation, restoring its public finances, and its competitiveness."
In theory, a lower credit rating makes borrowing more expensive.
The return for investors buying French debt indeed did rise after the announcement.
The yield on French government 10-year bonds rose more than 20 basis points to 2.389% from 2.158%.
Read more of this report from the BBC.