Afterward, she became a high school drawing teacher, but began to study art history at the École du Louvre and the University of Paris.

In 1941, during World War II, Valland was put in paid service and became the overseer of the Jeu de Paume Museum at the time of the German occupation of France.

[1] While the Nazi plundering was being carried out, Rose Valland began secretly recording as much as possible of the more than 20,000 pieces of art brought to the Jeu de Paume Museum.

[2] In addition, for four years she kept track of where and to whom in Germany the artworks were shipped and risked her life to provide information to the French Resistance[4] about railroad shipments of art so that they would not mistakenly blow up the trains loaded with France's priceless treasures.

The museum was visited by high-ranking Nazi officials, and Valland was there when Reichsmarschall Hermann Göring came on 3 May 1941 to personally select some of the stolen paintings for his own private collection.

[6] After ejecting some old German soldiers who were escorting the shipment they opened up some of the crates and found many paintings which Rosenberg had last seen hanging on the walls of his family's apartment in Paris.

After Jaujard had put her in touch with Captain James Rorimer of the Monuments, Fine Arts, and Archives program it took months of relationship building before she decided to turn over her most important records.

To assist in her efforts to locate stolen works of art and return them to France, Valland applied for and received a commission first as a lieutenant and then captain in the French First Army on 4 May 1945.

[2] Displaying initiative, Valland approached German military staff (whose names she had recorded while at the Jeu de Paume) and was able to confirm the location of several additional, previously unknown repository sites.

In 1946 Valland was put in charge of the Fine Arts activities for the French Oversight Board where she assisted in the recovery of numerous paintings, sculptures, precious coins, and tapestries belonging to France.

In a 2013 report to the French Senate, it is estimated that due to the efforts of Valland, it had been possible for the Commission de Récupération Artistique and the Allies to locate approximately 60,000 works, with three-quarters of them returned to France before 1950.

From the French government Valland received the Legion of Honour, was made a Commandeur of the Order of Arts and Letters and was awarded the Médaille de la Résistance.

[13] Following the end of the Second World War Valland began a relationship with Joyce Helen Heer (1917-1977), a Liverpool born secretary-interpreter at the Embassy of the United States.

[20] Valland was an inspiration for the character of Claire Simone, portrayed by Cate Blanchett in the George Clooney-directed film The Monuments Men, released in February 2014.

[21] In Paris, France, in her memory, two commemorative plaques were inaugurated : one in front of the Musée du Jeu de Paume, in the Jardin des Tuileries, and the second on the building where she lived with Joyce Heer, in the 5th arrondissement.