Last Sunday's election "cannot be considered representative," ministry spokeswoman Agnès Von Der Muhll said, citing the sidelining of opposition parties and "irregularities" denounced by several candidates.
She said the French government was "deeply worried" about the prospects for Venezuela after the vote, saying it would "not help resolve the very serious economic and social crisis besetting the country."
68 percent of the votes
Maduro won 68 percent of the votes, but more than half of voters -- a record 52 percent -- abstained from going to polling stations in a country long wracked by crises.
"The historically low participation rate confirms that a majority of Venezuelans do not consider him legitimate nor credible," Von Der Muhll said.
Maduro's opponent, ex-army officer Henri Falcon who scored 21 percent, has also said the vote had no "legitimacy" and called for a new election by the end of this year.
Washington has also denounced the vote as a "sham" and tightened sanctions against the government, though the European Union has not yet indicated if it will do the same.
The International Monetary Fund estimates that Venezuela's GDP will continue to shrink this year, with hyper-inflation expected to get worse.
Venezuela has long relied on its oil exports, but production has dropped to its lowest level in 30 years despite a recent rise in prices.