The task force said today the court-appointed administrator of Gurlitt's estate this week received the suitcase, which had been kept at the hospital, and reported finding the light-blue landscape.
It said it will check whether the work was stolen by the Nazis, as it is doing with many other works in Gurlitt's collection.
Experts believe Monet may have painted the work around 1864. The task force says it appears very similar to the French artist's "View of Sainte-Adresse."