The warning came as media watchdogs accuse the government of a press crackdown since lawmakers passed a highly contested constitutional reform that opposition parties say allows President Faure Gnassingbe to extend his rule.
Togo's High Authority for Audiovisual and Communications, or HAAC, last month suspended authorisations for foreign journalists to travel to cover April 29 legislative elections.
In its warning letter, HAAC accused RFI of ignoring repeated appeals for neutrality in coverage of Togo's situation and the elections.
"These repeated errors in your reporting are not only damaging to the image of Togo but also violate the fundamental principles of journalism," it said.
If the violations continued, the HAAC would "take appropriate measures, including the suspension of your right to broadcast in the national territory until further notice."
RFI did not immediately respond to a request for comment about the HAAC statement.
French journalist Thomas Dietrich, a critic of the authorities, was also expelled shortly after entering Togo before the ballot.
Political tensions have been on the rise in Togo since the parliament approved the new constitution in April, switching the West African country from a presidential to a parliamentary system.
Under the reform, the presidency becomes a largely ceremonial post elected by lawmakers. Power will shift to a new president of the council of ministers, a kind of prime minister role.
That post will be taken by the head of the ruling party in parliament. Gnassingbe's Union for the Republic, or UNIR party, won 108 out the 113 seats in parliament in April's election.
It means Gnassingbe can hold the post every six years if his party maintains a parliamentary majority. Under the past constitution, he would have only been able to run one more time as president.
For critics, the reform is an "institutional coup" tailor-made for Gnassingbe, 57, to avoid term limits and extend his family's more than five-decade political dynasty.
First put in power by the army in 2005 after his father's death, Gnassingbe has won four elections, all denounced as unfair by the opposition.
His father also ruled Togo for nearly four decades after leading a military coup.