French national Juan Remy Quignolot has been accused of spying and conspiracy by prosecutors in the Central African Republic, nearly a month after he was arrested in the capital, Bangui, according to public prosecutor Eric Didier Tambo.
"The accusations are of espionage, illegal possession of military and hunting weapons, criminal association, harming domestic state security and conspiracy," Tambo told French newswire AFP, adding that any trial would take place within the next six months.
"In cases of harming domestic security, you're talking about lifetime forced labour," he said, referring to the Central African punishment if he is convicted.
When he was arrested on 10 May, Quignolot allegedly had a large quantity of weapons in his possession while he claimed to be a journalist. A photo of his arrest shows his hands bound behind his back, sitting behind a mound of weapons and military clothing.
France called the arrest and photos "manipulation".
The Frenchman reportedly worked occasionally as a security guard for several aid organisations in the country.
Former colonial power France froze budgetary aid and military cooperation with CAR two days ago, calling his arrest and charges part of an anti-French disinformation campaign backed by Moscow.
"The Russians are involved, but the CAR is an accomplice at best," said the French foreign ministry.
"The CAR authorities have several times made commitments which they haven't upheld, both politically with regard to the opposition and in its behaviour towards France, which is being targeted by a massive disinformation campaign," the ministry added.
Russian Valery Zakharov, a close adviser to CAR President Faustin Archange Touadera, tweeted about the arrest.
France had a military presence in the country, Operation Sangaris, to help quell the conflict after then-president François Bozizé was toppled in 2013. Sangaris pulled out in 2016, following elections.
However, a strong Russian presence has grown in the unstable country over the past three years - weapons and "instructors" were sent in 2018 to train CAR forces.
It has made sizeable investments in CAR's minerals sector, which include gold, diamonds, copper and uranium.
Last December, Moscow and Rwanda sent hundreds of military personnel to work on behalf of Touadera as a coalition of armed groups mounted an attempted coup ahead of presidential elections. He was able to regain control over a large part of the country that had previously been in militia hands.
Late last month, French President Emmanuel Macron told France's Journal du Dimanche newspaper that "anti-French talk has provided legitimacy to predatory Russian mercenaries at the apex of the state, with a President Touadera who today is a hostage of the Wagner group," referring to the Russian paramilitaries who carry out operations for the Kremlin.