The idea of visiting Paris in January to see six exhibitions and two repeats in five days may seem excessive to some people, but Paris’s museum offerings this northern winter were so impressive it was impossible to resist. At Frank Gehry’s lofty Fondation Louis Vuitton, hordes lined up, day and night, in temperatures of five below, to see Icons of Modern Art: The Shchukin Collection from Russia. It was much the same at the Centre Pompidou, which, happily, is celebrating its fortieth anniversary this year with huge retrospectives of Cy Twombly and René Magritte, fifty exhibitions and performances in forty French cities, and its single outpost, Malaga. Architects Renzo Piano and Richard Rogers, thirty-somethings when they designed the Pompidou, are now international icons.