The treaty of Nancy will be signed on Europe Day, in the town hall on the 18th-century Place Stanislas, by the French president, Emmanuel Macron, and the Polish prime minister, Donald Tusk. It will cement a reconciliation between two countries that have been estranged within the EU for most of the last three decades.

France’s lack of enthusiasm for EU enlargement and its pursuit of cooperation with Russia were the main reasons for the strained relationship. Poles still bitterly remember Jacques Chirac telling central European countries that endorsed the 2003 invasion of Iraq that they had behaved badly and “missed a good opportunity to shut up”.

Warsaw has long relied exclusively on the US and Nato for its security and has resisted any EU role in defence. But with Donald Trump pursuing rapprochement with Russia, Poland’s arch-foe, and his willingness to let Moscow prevail in Ukraine and reduce US military exposure to Europe, Tusk is rushing to build closer ties with Paris, Berlin and London in a quest for extra security insurance.