France's embassy did not give a reason for Nicolas de Bouillane's expulsion by the Belarusian foreign ministry.
France's ambassador has been ordered out of Belarus and has already left the country, according to the French embassy in Minsk.
The embassy did not say why the ambassador, Nicolas de Bouillane, had been told to leave by the Belarusian foreign ministry.
"Ambassador Nicolas de Lacoste left Belarus today," said an embassy spokesperson.
According to Belarusian media, the ambassador was expelled because he never presented his credentials to President Alexander Lukashenko.
In a message on its website, the French Embassy in Belarus said that the diplomat had presented "the figurative copy of his credentials" to Foreign Minister Vladimir Makei last December.
"The Belarusian foreign ministry has requested that the ambassador leave before October 18," the spokeswoman said.
Meanwhile, Minsk said in a statement that it had also recalled its ambassador to France, Igor Fissenko, over the matter.
France, like other EU countries, has not recognised the results of last August's presidential election, which granted Lukashenko a sixth term despite widespread reports of electoral fraud.
The outcome sparked massive protests lasting several months, unprecedented in the former Soviet republic, an ally of Vladimir Putin's Russia.
The European Union and the United States adopted a series of sanctions against the Belarusian regime after a brutal crackdown against Lukashenko's opponents.
But the 67-year-old leader, who accuses Western governments of instigating the protests in the hope of provoking a revolution, is resisting sanctions for now, thanks to support from Moscow.
Belarus has also recently severed relations with other Western countries.
In March, it expelled all Latvian embassy staff, including the ambassador, because the Latvian authorities had used the Belarusian opposition flag at an ice hockey championship.
And in August, Minsk withdrew its agreement for the appointment of American ambassador Julie Fisher, who was confirmed in December as the first US envoy to the country since 2008.
Since then, the regime has managed to put an end to the protests, imprisoned hundreds of opponents and shut down dozens of media organisations and NGOs. Opposition leaders have all been jailed or forced into exile.
Last month, a Belarusian court sentenced one of the main opposition figures, Maria Kolesnikova, to 11 years in prison.
She is the only leader of last year's protests -- which sometimes brought together hundreds of thousands -- still in the country.
Sviatlana Tikhanouskaya, who opposition and Westerners believe won the presidential election against Alexander Lukashenko, is in exile in neighbouring Lithuania.
During the year following the election, she mobilised world leaders, calling on the international community to press for a new presidential election in Belarus.