PARIS, Sept. 17 — On Monday President Nicolas Sarkozy of France, who is increasingly faulted, even by his own government, for usurping the responsibilities of his top ministers, stepped into the role of culture minister. At a low-key ceremony he inaugurated La Cité de l’Architecture et du Patrimoine, (the City of Architecture and Heritage) in Paris, which reopened after an $114 million , decade-long makeover. “I commit myself fully to this mission, to give back the possibility of boldness to architecture,” he said in his speech. Mr. Sarkozy turned the occasion into a promotion of French architecture throughout the ages, inviting some of the world’s top architects to the museum (and to lunch at the Élysée Palace) and winning their endorsements along the way. President François Mitterrand built the glass pyramid at the Louvre, the Grande Arche de la Défense, the Bastille Opera and the François Mitterrand French National Library; Jacques Chirac created a museum devoted to African, Asian, ...