"The customs services are currently proceeding with the complete and thorough examination of the cargo and crew of a North Korean ship which called at Mayotte," foreign ministry spokesman Jean-Baptiste Mattei said.
The inspection was being carried out under UN Security Council Resolution 1718 declaring an arms embargo on North Korea in the wake of its October 9 nuclear test.
A source in the ministry later confirmed that nothing had yet been found and that the inspections would continue until the end of the week.
Port authorities in Longoni, Mayotte's only port, said the North Korean boat was a cement manufacturer called the "An Nok Gang", which arrived on the Indian Ocean island on November 11 to discharge 3,500 tons of cement out of 8,500 tons being transported. They said it had previously made a stop in Indonesia.
"We particularly exercise vigilance towards cargo transported by North Korean ships, as well as those coming from or going to the Democratic People's Republic of Korea (DPRK)," Mattei said.
"France immediately took restrictive measures regarding the DPRK on visas and bilateral co-operation" after the October nuclear test, he said.
"This inspection shows France's determination in the area of surveillance of proliferation activities," added a French diplomat, requesting anonymity.
"This applies to North Korea as well as to other countries."
The diplomat said that the inspection of the North Korean freighter could last "a very long time".
"There was no boarding for inspection, the ship had berthed," he added.
Meanwhile, a US Congress-appointed panel on Thursday sought broader sanctions against Chinese firms proliferating unconventional weapons and wanted Beijing to inspect ships travelling to or from nuclear-armed North Korea's ports.
The United States-China Economic and Security Review Commission in its annual report called for Congress to urge the government to seek agreement with China to carry out inspections at sea of ships travelling to or from North Korean ports.
It also called for a joint operation from Beijing and Washington to inspect for suspected contraband shipping containers from the Stalinist state.
And in the keynote speech of a week-long trip to Asia, US President George W. Bush urged North Korea to take "a peaceful path" to ending the tense crisis over its nuclear weapons program and prove its good faith by taking concrete steps.
He also urged regional leaders to make it clear to Pyongyang that transferring nuclear know-how to other states or terrorist groups "will not be tolerated."
The French foreign ministry on Thursday underlined that the European Union was soon due to adopt a "common position" on restrictive measures being taken against North Korea.

Copyright AFP (Agence France-Presse), 2006