Authorities in France temporarily blocked trains from Italy in an attempt to stop north African migrants from entering the country.
The Italian foreign ministry said the French move was "illegitimate and in clear violation of general European principles".
Services were later resumed.
The source of the concern on France’s part is Italy’s decision to issue temporary residence permits to thousands of Tunisian migrants, allowing the bearers to travel freely in many European countries.
European Council president Herman van Rompuy yesterday said that neither France nor Italy had broken European law, but he expressed concern over respect for the principle of the Schengen agreement guaranteeing the free movement of persons.
Italy’s Internior Minister, Roberto Maroni looked forward to a scheduled April 26th summit meeting, saying he is confident the countries will be able to smooth over any differences then.