While the museum is packed with some of Degas', Cezanne's, Gauguin's and Toulouse-Lautrec's best work, only around 4,400 pieces can be shown at any one time.

That leaves some 164,000 paintings and sculptures in its stores, which is set to grow even further with the massive donation by a Texan couple of their 350 million euro ($372 million) art collection to the French capital.

Businessman Spencer Hays and his wife, Marlene, in November signed off on the first installment of 187 works for the Musee d'Orsay, including pieces by Degas and Modigliani worth around 173 million euros.

Their gift, the biggest from a foreign benefactor to France since World War II, also includes important work by Bonnard, Vuillard and Redon.

Faced with such pressure, the museum has bought a neighboring 18th-century mansion on the banks of the Seine to house its library and research center on the post-impressionists.

The idea of a fine art museum at a railway station was revolutionary when the museum opened in December 1986.

Built like the Eiffel Tower and the Grand Palais for the Universal Exhibition in Paris in 1900, it had the same architectural exuberance.

Having survived demolition plans in the 1970s, it was converted into a museum for mostly French art dating from the revolutions of 1848 to the outbreak of World War I as one of the late French president Francois Mitterrand's grand projects to renew the French capital.

A runaway success from the start, with its architectural elegance and head-turning collection equally praised, Rey says: "One can no longer imagine the museum anywhere but in this station."