Minutes after the Kunstmuseum Bern in Switzerland revealed for the first time a list of artworks Cornelius Gurlitt had stashed in his second home near the Austrian Alps, its promise of full transparency seemed to clear away decades of murky silence about a delicate Pissarro painting showing the Louvre in Paris and bridges spanning the Seine.

The picture, listed as “Paris Kathedrale,” was one of 250 artworks included in the “Salzburg collection” of Mr. Gurlitt, who died in May and left his entire estate to the museum.