"This new provocation is unacceptable between neighbouring countries and partners at the heart of the European Union," a ministry spokesman said in a statement a day after Di Maio met the protesters on French soil.
"Mr Di Maio, who has governmental responsibilities, should ensure that he does not impair with its repeated interferences our bilateral relations, in the interest of both France and Italy," the spokesman said.
Di Maio, head of the anti-establishment Five Star Movement (M5S), announced Tuesday he had met near Paris with yellow vest leader Christophe Chalencon and candidates on a yellow vest list for European Parliament elections in May, led by Ingrid Levavasseur.
He invited them and other yellow vests to a follow-up meeting in Rome, claiming on Twitter that "the wind of change has crossed the Alps." Tensions have flared between the two countries since the Five Star Movement and far-right League party came to power in a coalition in Italy last June.
That prompted France to summon Italy's ambassador in protest. And De Maio's fellow deputy prime minister, Matteo Salvini, has lambasted President Emmanuel Macron directly by saying he is "close, with all my heart... to the French people, the millions of men and women who live in France under a terrible government and terrible president".
The "yellow vest" protests against fuel taxes began in rural and small-town France in late November, before ballooning into a wider revolt against Macron's policies and governing style.
The French president is hoping to forge an alliance of pro-European centrists ahead of the bloc's parliamentary vote, against a wave of populist movements in several European countries.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)