A Dutch lawyer who lied about a former Trump campaign aide’s contact with a Russian intelligence agent was sentenced Tuesday to 30 days in jail and ordered to pay a $20,000 fine.

It was the first sentence imposed in special counsel Robert Mueller’s investigation into Russian meddling in the 2016 election.

Alex van der Zwaan 33, pleaded guilty in February to lying about his communications with Rick Gates — a longtime business associate of former Trump campaign chairman Paul Manafort — and Gates’ contact with Russian operative Konstantin Kilimnik in the final months of the presidential campaign.

Gates, a former adviser for the Trump campaign who’s cooperating with Mueller, told van der Zwaan that Kilimnik was connected to a Russian spy outfit.

A prosecutor on Mueller’s team told the federal judge in Washington, DC, that she should set an example with his sentencing.

“We count on people to tell us the truth,” Andrew Weissman told District Judge Amy Berman Jackson. “Ther e are consequences for withholding documents and consequences for lying to the government.”

Van der Zwaan’s lawyers pleaded for probation, a fine and permission for him to return home to London and his wife, the daughter of a Russian oligarch.

But Jackson said jail time was needed to drive home the point about lying.

“The s e were not mistakes. These were lies . This was lying during the course of a federal investigation ,” Jackson said, adding that van der Zwaan shouldn’t be able to “write a check and walk away.”

Van der Zwaan apologized in a statement. He will have to serve two months of supervised release after completing his stay at the federal prison in Allenwood, Pa.

Van der Zwaan, an associate of the international law firm of Skadden & Arps, worked with Manafort when he was a political consultant in Ukraine.

He is the fifth person to plead guilty in Mueller’s probe but the first to be sentenced.

Manafort, who has pleaded not guilty, is expected to stand trial in July.