After the World War One, a new fate brought about radical changes to the Orangerie. Indeed, in 1921, the State assigned the building to the Under-Secretariat of State for Fine Arts, together with its counterpart the Jeu de Paume, built in 1862 on the terrace lining the rue de Rivoli. The idea was to provide a space to exhibit works by living artists. It was at this moment that Georges Clemenceau (1841-1929), President of the Council, suggested that the large Water Lilies set that Claude Monet (1840-1926) was painting at the time and which he had donated to the State be installed at the Orangerie rather than in the courtyard of the brand new Musée Rodin. The donation was formalised in 1922.
Claude Monet spent a lot of time on the architectural design alongside the architect Camille Lefèvre (1876-1946). In the end, 8 panels, each 2 metres high and spanning a total length of 91 metres, were arranged in 2 oval rooms that form the symbol of infinity. Their east-west orientation places them in the path of the sun and along the historical axis of Paris which runs from the Arc de Triomphe to the Louvre. A vestibule provides access to the two rooms and marks the transition from the outside world. Finally, the natural light that enters though the ceiling immerses visitors in a state of grace, as intended by the painter.
The "Musée Claude Monet" was inaugurated by Clemenceau on 17 May 1927, a few months after the artist's death. It was transformed into an annex of the Musée du Luxembourg, and the building became the Musée National de l’Orangerie des Tuileries.