Sonko has not yet decided whether to appeal the sentence in the libel case, his lawyer Bamba Cisse told The Associated Press.
Sonko was also ordered to pay about $330,000 to Tourism Minister Mame Mbaye Niang, who accused the politician of defamation and public insults.
Neither Sonko nor his lawyers were present on Thursday when the verdict and sentence were delivered.
Each of Sonko’s previous court appearances led to protests in the streets of Dakar, the capital, and Sonko himself was forcibly removed from his vehicle by police on two occasions. Demonstrations have taken place not only in Dakar but in cities throughout the country.
Sonko’s supporters see the charges against him as the latest attempt to cut short his political career. Sonko finished third in Senegal’s 2019 presidential election and has called on President Macky Sall to declare publicly that he won’t seek a third term.
The ruling party says Sall should be allowed to run after a constitutional change in 2016 — made while Sall was president — which changed presidential terms to five years.
Sonko also faces rape charges based on accusations from a female employee of a massage salon who said she was assaulted by him. If convicted, he faces up to 10 years in prison and would be barred from running for president. No date has been set yet for the that trial.