AMSTERDAM — The International Criminal Court on Monday sentenced Jean-Pierre Bemba, a former Congolese vice president who was acquitted of war crimes in June, to a 300,000 euro fine for Witness Tampering.

Mr. Bemba, who has been barred from running in the presidential elections in the Democratic Republic of Congo because of the conviction for witness tampering, was also sentenced to 12 months in prison, but that was reduced to zero because of time already served.

“Future accused persons can look at Mr. Bemba’s conviction as a cautionary example as to what consequences obstructing the administration of justice can have,” said Judge Bertram Schmitt. “Mr. Bemba’s acquittal in the main case should have been the end of his exposure to the court, yet he continues to have the specter of this institution hanging over him.”

The acquittal of Mr. Bemba on war crimes charges, which came on appeal, came as a surprise and raised the prospect he could return to Congo and re-enter politics. A final decision is expected Wednesday on whether the witness tampering conviction, for which he must pay the equivalent of $350,000, makes him ineligible to run.

Mr. Bemba headed the Movement for the Liberation of Congo party and its affiliated militia. After he lost an election to Laurent Kabila in 2006, he was sent to The Hague to stand trial for atrocities committed by his troops in the neighboring Central African Republic in 2002 and 2003.

His initial conviction was reversed on appeal in June. Judges said that prosecutors had failed to show he had enough control over troops to bear responsibility for their wrongdoing and that he could not be convicted beyond a reasonable doubt.

Mr. Bemba, who was arrested in Belgium in 2008, was the highest-ranking politician to be convicted by the court and his initial conviction in 2016 was seen as a watershed moment.

The conviction for war crimes was taken as a sign that politicians and military officials could be held liable for conduct outside their homelands. In addition, the court found for the first time that rape could be interpreted as a weapon of war.

The court overturned the verdict in June, however, by a 3-to-2 vote, citing a series of legal errors. It did not question that a militia that Mr. Bemba founded and financed to assist his ally in the Central African Republic had committed atrocities, but found that Mr. Bemba was a “remote commander” who would have had difficulty knowing what his forces were doing.

Mr. Bemba, who has family in both Belgium and Congo, did not attend the hearing on Monday.