Mr Jupp has been shuttling between the Foreign Ministry and the Paris town hall, where he has been with President-elect Jacques Chirac, planning the new government.
No one doubts Mr Jupp's energy. Since Mr Chirac declared his candidacy for the presidency last November, Mr Jupp has held down several jobs. As well as being Foreign Minister, MP for a Paris district and Chirac campaigner, he has deputised for Mr Chirac as chairman of the Gaullist RPR party and campaigned to be mayor of Bordeaux, in the municipal elections next month.
Some days have involved early-morning radio interviews,meetings at the Foreign Ministry and visits to New York for the nuclear non-proliferation talks, returning in time for evening campaign meetings.
Mr Jupp, 50 in August, has been a Chirac supporter from early in his career. In 1976 he was recruited to Mr Chirac's private office. Almost immediately, Mr Chirac became Prime Minister in the government of President Valry Giscard d'Estaing. Mr Jupp stayed on. Two years later, when Mr Chirac became Mayor of Paris full-time, Mr Jupp became director of finances at the Paris town hall.
He received his first ministerial post in Mr Chirac's first "cohabitation" government of 1986, and became secretary-general of the RPR party when that government left office in 1988. With the return of the right to government two years ago, Mr Jupp became Edouard Balladur's Foreign Minister, and continued after he backed Mr Chirac for the presidency against Mr Balladur, becoming his campaign organiser.
There were times in the campaign when Mr Chirac feared Mr Jupp would defect to the Balladur camp. He remained loyal. "I am not campaigning against Mr Balladur," he said. "I am campaigning for Mr Chirac."
There are criticisms of Mr Jupp - those commonly applied to the lite of France's premier post-graduate college, the Ecole Nationale d'Administration. A prize-winner throughout his school and college career, Mr Jupp is described as a "cold fish" and "confident of his own abilities". No one questions his intellectual powers or administrative ability. He is an impressive media performer.
He has few enemies apart from the chairman of the National Assembly and fellow Chirac supporter, Philippe Sguin. The two are rivals and complete opposites. Mr Jupp is ascetic, Nordic, restrained and conformist. Mr Sguin is thick-set, Mediterranean, forceful and an iconoclast. Mr Jupp is too "Balladurist" for Mr Sguin, dresses too consciously in a certain "English" style, likes his claret and has Marks & Spencer muffins for breakfast.
Their differences extend to policy. Mr Jupp is a Europhile and supports the single European currency, a strong franc, and cutting deficits.
Mr Sguin is as close to a Eurosceptic as France can offer. He campaigned against the Maastricht treaty and favours a weaker franc in order to reduce unemployment.
Mr Sguin thinks that Mr Jupp is aloof from France's social problems. Mr Jupp sees sound money as the prerequisite for any solution.
Mr Chirac is thought to have preferred Mr Jupp as the man most likely to calm foreign exchange markets and get on with France's European partners.
Mr Jupp does not deny that he is ambitious. Informed speculation is that he would like to be Prime Minister for two or three years. By the time he is about 56, he will ready to succeed his mentor at the Elyse.