The past extent of that influence was shown as Mr Mitterrand was greeted by President Le Duc Anh and the Prime Minister, Vo Van Kiet, at the presidential palace in Hanoi, built in colonial style at the turn of the century for the French governors of Indo-China. A military band played the Marseillaise and the Vietnamese national anthem before the leaders went inside for talks.
The Vietnamese had to fight the United States and France for independence, but hold the latter in more affection. Older people in all three Indo-Chinese nations - Laos, Cambodia and Vietnam - retain their respect for the French language and culture. Most of their leaders formed their ideas in France as workers or students, from the father of Vietnam's revolution, Ho Chi Minh, to Cambodia's murderous Pol Pot. Whether this will give France an advantage as Indo-China opens up for business remains to be seen.
Despite more recent and more bitter memories of the US presence in the region, the lifting of Washington's embargo is seen as the key to Vietnam's future prosperity, because it would open the way for lending by the International Monetary Fund (IMF) and other multilateral institutions. France, the third largest aid donor to Vietnam after Japan and Sweden, is helping Hanoi to clear its arrears with the IMF, and has led calls for the embargo to be ended.
Hanoi undoubtedly hopes Mr Mitterrand's visit will add impetus to the campaign, but French businessmen see the trip as a chance to establish a foothold in Vietnam before they face US competition: yesterday the electronics firm Thomson-CSF said it had been selected to supply and install a new air traffic control system at Ho Chi Minh City's airport.
In Cambodia tomorrow, President Mitterrand will meet the former ruler, Prince Norodom Sihanouk, who also welcomed Charles de Gaulle to Phnom Penh in 1966. France is the main advocate of a presidential election, which the Prince would almost certainly win, although such a poll is not envisaged in the United Nations peace plan for the country.
France is seeking to use its leading role in the UN process, and its status as a former colonial power, to re-establish itself in Cambodia. It has insisted, for example, that French should have equal status with English in the workings of the UN Transitional Authority in Cambodia, and has set up relay stations to broadcast French radio and television on local channels. The Alliance Francaise in Phnom Penh has been reopened, and a new bakery ensures that croissants are widely available. A Paris bus even plies the streets of the Cambodian capital.
Most of the wine on sale, however, is Australian, and the realities of South-east Asia's geographical position and cultural priorities keep breaking through in other ways. Younger Cambodians overwhelmingly choose to learn English, and Street 184 in Phnom Penh is where they go. The open-air language schools which line its verges have led to it being nicknamed 'English Street', and posters advertising new supplies of English primers have been plastered on the walls surrounding French colonial villas.
'French policy towards Cambodia is in many ways anachronistic and sentimental,' one diplomat told Reuters news agency. 'They do seem to see their language and culture as a way to revive French influence. I think it is an uphill battle, as no one wants to learn French. It's no good for international business in this region, and Cambodians can't afford the luxury of culture at the moment.'