Paris (CNN) After months of simmering tensions between Rome and Paris, the battle for the soul of Europe just got a lot uglier. On Thursday, France recalled its ambassador to Rome for the first time since 1940, when fascist leader Benito Mussolini declared war. This time the French foreign ministry blamed a war of words -- "the repeated accusations, baseless attacks and outlandish claims" of Italy's populist government.

The barbs between Italy's populist politician Matteo Salvini and the French President Emmanuel Macron have been regular and personal. Last month Italy's far-right Interior Minister and Deputy Prime Minister said he hoped the French people would soon manage to rid themselves of a "terrible president." Macron, for his part, has likened rising nationalism to leprosy, declaring that if the populist nationalists regard him as their enemy, "they are right."

Macron and Salvini are locked in a deepening war of words.

But the straw that appears to have broken the camel's back came in the shape of a meeting between Italy's other deputy PM Luigi Di Maio and France's own populists, the yellow vests. The meeting, which took place on Tuesday on the outskirts of Paris, led Di Maio to declare that the winds of change had now crossed the Alps.

Following France's decision to recall its ambassador, Di Maio tried to justify the meeting. "I wanted to meet with representatives of the 'yellow vests' and the citizens' initiative referendum group, because I do not believe that the future of European politics lies in the parties of the right or the left," Di Maio, leader of the populist Five Star Movement, wrote in a letter published in Le Monde.

The diplomatic row now threatens to spill over into the world of art. Leonardo da Vinci's legacy -- long a source of friction between Italy, where the renaissance master spent most of his life, and France, where he sought refuge and died -- is now being fought over all the more viciously.

Read More