PARIS—President Emmanuel Macron of France labeled Polish Prime Minister Mateusz Morawiecki a “far-right anti-Semite,” escalating tensions with Warsaw just days before the French leader faces re-election.

Poland’s foreign ministry summoned France’s ambassador in Warsaw on Friday after French daily Le Parisien published the comments as part of an interview with Mr. Macron.

Asked about an address Mr. Morawiecki recently delivered—comparing Mr. Macron’s outreach to Russian President Vladimir Putin to negotiation with Hitler—Mr. Macron told Le Parisien: “This is shameful. The Polish prime minister is a far-right anti-Semite who bans LGBT people.”

Poland’s Foreign Ministry didn’t immediately respond to a request for comment. The country doesn’t recognize same sex marriage, and its ruling Law and Justice party has vowed to halt the expansion of more liberal attitudes and laws regarding LGBT rights in Europe at the Polish border.

The Franco-Polish feud is testing the unity of Europe’s response to Russia’s invasion of Ukraine. It also undercuts the French leader’s diplomatic stature right before millions of French cast ballots in the first round of the election on Sunday. Polls show that far-right leader Marine Le Pen has begun closing in on Mr. Macron, who has neglected the campaign trail in order to focus on diplomatic solutions to the war in Ukraine.

Mr. Macron, who holds the European Union’s rotating presidency, helped build consensus for European sanctions that aim to cut Russia off from the global financial system. He has also kept an open channel to Mr. Putin, carrying messages between the Russian leader and Ukrainian President Volodymyr Zelensky.

Earlier this week, as horrific images began to surface of the slaughter of civilians in Bucha, a Ukrainian town near the capital of Kyiv, Mr. Morawiecki lambasted Mr. Macron during a speech in Krakow.

“President Macron, how many times have you negotiated with Putin? What have you achieved?” Mr. Morawiecki asked. “Would you negotiate with Hitler, with Stalin, with Pol Pot?”

In the interview with Le Parisien, Mr. Macron described Mr. Morawiecki as a supporter of Ms. Le Pen, adding: “Let’s not be naive. He’s trying to help her before the vote!”

Poland has been deeply frustrated with Mr. Macron’s push for “a new European security architecture” during his diplomacy with Mr. Putin. Poland, and some of its neighbors, view that as an effort that risks overriding the sovereignty of Ukraine and other Eastern countries, in favor of a deal that suits the French president and his re-election hopes.