The meeting is the first since the two countries signed a treaty of friendship and enhanced cooperation last May.

"We have very similar views on how to build Europe's strength, the sovereignty of Poland, of France, and of Europe," Tusk said on the eve of the visit.

As Europe ramps up its defensive capabilities in the face of Russia's four-year old invasion of Ukraine and US President Donald Trump's questioning of the Atlantic alliance, the two leaders will discuss the possibility of a Polish role in France's nuclear deterrent.

While France has specified it would retain full control over the decision to use force, Polish forces could contribute in areas such as early warning and air defense, both sides say.

- 'European preference' -

Macron's office said the two countries would also enter into a partnership on a "military communications satellite project," involving "French, Polish, and other European operators."

Another key issue is "European preference" for military procurement, which Macron has promoted. That's led to some tension with Eastern European countries, including Poland, strongly attached to their relationship with the United States.

Poland in recent years has massively invested in modernizing its armed forces, making it an attractive ally.

Poland's military spending is among the highest in NATO, expected to exceed 4.8 percent of GDP in 2026, far ahead of most countries in Europe.

But the country has placed "colossal orders for American F-35s, Apache attack helicopters, Patriot missiles, and Abrams tanks," a European diplomat close to the matter told AFP.

Nationalist President Karol Nawrocki, a rival to Tusk, is opposed to Poland's participation in the EU's SAFE Security Action For Europe) program, citing a threat to his country's "independence", even if it would contribute tens of billions of euros to its defence.

- Pro-European fold -

Poland is now led once again by a pro-European government following Tusk's electoral victory in 2023, but it remains fundamentally attached to its relationship with the United States.

That relationship has been tested by Trump's repeated insults against Europe and the war he started with Iran.

"Washington's strategy has indeed changed" toward Europeans, the Prime Minister told a press conference. But "Polish-American and Euro-American relations" remain "very important," he said.

Macron and Tusk will also welcome Hungary's return to the pro-European fold after the electoral defeat of Prime Minister Viktor Orban, who had cast himself as the leader of the illiberal and nationalist camp in the EU.

Monday's meetings are being held in Gdansk, a symbol of Europe's upheavals in the 20th century.

The port city, which lies about 150 kilometers from the Russian enclave of Kaliningrad, was the site of iconic shipyards where the pro-democracy Solidarnosc (known in English as Solidarity) movement was born, that eventually resulted in the end of Soviet rule.

Macron began his trip with a visit to a nearby French military cemetery, following in the footsteps of previous visiting French presidents.