France and Germany have pledged to strengthen their alliance and deepen a bilateral post-war reconciliation treaty in a bid to show that the EU’s main axis remains strong and ready to counter growing Eurosceptic nationalism in the bloc.

With their signature in 1963, German Chancellor Konrad Adenauer and French President Charles de Gaulles laid the ground for the beginning of an unexpected friendship. The document, with just under six pages, did not define any political goals but was rather a blueprint for what became later the Franco-German engine on the European level.

The extension to the Élysée Treaty approved by the German and French cabinets will be signed by Chancellor Angela Merkel and French President Emmanuel Macron in the German border city of Aachen on 22 January – an ancient symbol of European concord.

On the same day, both national parliaments are also meant to ratify the treaty.

German government spokesman Steffen Seibert, called the decision “an issue of historical importance”, after the cabinet in Berlin approved the signing of the contract on Wednesday (9 January).

“Both states will deepen their cooperation in foreign affairs, defence, external and internal security and development and at the same time work on strengthening the ability of Europe to act independently,” states the treaty text, according to Reuters.

In Paris, Macron’s office said the Élysée Treaty extension would help both European powers tackle “the challenges they will be confronted with in the 21st century”.

“(We) envisage deepening our engagement in favour of security and prosperity of our peoples in the framework of a more sovereign, united and democratic Europe,” the statement said.

Although the final document text has not been published yet, it covers the whole range of state cooperation between Germany and France, including common approaches to foreign and security policy objectives.

The document, negotiated over the past year, is short on details but stipulates that a priority of German-French diplomacy will be for Germany to be accepted as a permanent member of the United Nations Security Council.

Germany has for years sought greater influence within the international body, to which its closest allies the United States, Britain and France belong.

With this step, Germany also abandoned the initial idea floated by German Finance Minister Olaf Scholz in late 2018 that France would give up its UN Security Council seat and turn it into a common EU seat in the future.

While making clear that Germany and France remain committed to the EU and NATO defence alliance, the agreement also signals that Berlin and Paris will combat efforts by some nationalist politicians in Europe to erode the EU.

“Germany and France are making clear that to solve future questions, we need more, not less cooperation,” German Foreign Minister Heiko Maas said.

Facing new challenges from President Donald Trump in the United States as well as EU governments in Italy, Poland and Hungary, Merkel and Macron are keen to head off any breakthrough for Eurosceptic parties in the European Parliament elections in May.

The treaty further outlines closer cooperation between national intelligence services and police in fighting terrorism and organised crime, and a commitment to moving towards economic convergence.

“Both states will deepen the integration of their economies towards a German-French economic area with common rules,” said the treaty text, referring also to calls for the harmonisation of economic law. In addition, they will set up a panel of experts to give economic recommendations to each government.

Other areas of cooperation include culture, health, innovation and transport.