It was a moment that revealed one of the possible shortcomings of Mr Annan as he prepares to ascend to the position as the world's number one diplomat: he is not a well-known figure beyond the United Nations community. This could matter. His face is not familiar either to the heads of government with whom he will have to deal in mediating global crises or to the public, in the United States and beyond, to whom he must sell an institution whose standing is dangerously low.
Mr de Charette's befuddlement did, however, equally expose remarkable ignorance on his part. Mr Annan, 58, has been a civil servant of the UN for no less than 30 years. In the past few years, especially since his appointment in 1993 to the critical position of Under Secretary General for Peacekeeping, he has been a pivotal figure in the UN's business, not least in Africa and the Balkans.
But then this is perhaps because Mr Annan, above all, was the choice of the English-speaking contingent in New York, that is Britain and United States. From Ghana, he speaks English as his first language - although his French his flawless. More than that, however, he is considered by London and Washington to be the one senior UN official who is entirely on their diplomatic wavelength.
The Americans first signalled their appreciation of Mr Annan in 1993 during the planning for the ultimately disastrous UN mission in Somalia. Washington more or less forced through his elevation to the top peace- keeping post. And it was Mr Annan to whom the Americans turned at the end of 1995 when, finally, it was agreed that the UN mission in Bosnia should be replaced by a Nato-led force. Under US and British pressure, Boutros Boutros Ghali agreed to relieve Mr Annan temporarily from his peacekeeping role to oversee the transition in the Balkans from the UN blue helmets to the Nato mission.
Mr Annan clearly has a hard shell. His tenure as peacekeeping chief was not a happy one. The Somalia intervention was shrouded in disaster when 18 US soldiers were dragged through the streets of Mogadishu and killed. The US pulled out and set about assigning the blame for the debacle to the UN. Likewise, the UN's refusal to agree to firm military action against the Serbs in Bosnia further diminished the organisation's reputation in Washington especially.
But Mr Annan inspires fierce loyalty among his staff. He is credited with building the most efficient and competent department in all of the UN hierarchy - one that is remarkably free of the usual dead wood of UN incompetents. He is articulate, unfailingly kindly in his demeanour - even when he is chastising someone for poor performance - and speaks in forthright and uncomplicated terms that is unusual for a diplomat in an organisation as politically fraught as the UN.
He has also not been shy in defending the blue helmets and making the case that the errors of missions such as those in Somalia and Bosnia were ultimately down to the Security Council members who authorised them.
"Peacekeepers are usually the first on the ground, the last to leave, and the first to be criticised," he said at a 1994 press conference. "Quite frankly, the decisions have to be made by the capitals and the Security Council and not by the peacekeepers on the ground ... I think where we are presumed to have failed is when we are judged by unrealistic expectations. If we are expected to play the role as enforcers when we don't have the mandate and the resources, then we have failed".
Mr Annan is the first truly black African Secretary General. Many Africans, however, may feel that they know him no better than Mr de Charette does. In his adult life he has barely set foot on the continent, except for a two-year stint in 1972-74 to run Ghana's tourism ministry. Even his college education was mostly in the US, first at Macalester College in Minnesota and then at the Massachusetts Institute of Technology in Boston. His wife, with whom he has three children, is Swedish.
His appointment yesterday will not surprise many, however, especially those who have watched him nurture his relations with Washington and London. It was Mr Annan, for instance, who appeared as the lone senior UN staff member at a recent party in Madeleine Albright's private apartment and it was he who borrowed the ear of Malcolm Rifkind, the Foreign Secretary, for 15 minutes at a September reception in New York at the British mission for Commonwealth ministers.
Even officials loyal to Boutros Boutros Ghali have in recent days begun to say nice things about Mr Annan to reporters. They, like everyone in the UN, have jobs to keep.