Six of the country's seven component indexes that make up the leading index rose, the research firm said.
The biggest boosts for September came from improved unemployment claims figures, the yield spread, new factory orders, building permits issued for residential construction, the stock price index and a manufacturing measure of factory output added to unit labor costs.
On Monday, Moody's Investors Service joined credit rating agency Standard & Poor's in downgrading France's credit rating from AAA to Aa1, one notch from the top.
The Conference Board said Monday the leading index for France rose 0.6 percent in September to 114.9.
The value of the leading index is derived from its comparison to 2004, which was assigned a base value of 100.