In the mid 1990's, Soviet declassified documents revealed that many
Impressionistic works of art looted/stolen from museums and private
collections by the Nazi's during WWII, somehow found their way to the
Hermitage and Pushkin museums. One Degas, of several in the Hermitage,
"Place de la Concorde" is of interest to me.  Has anyone uncovered the
details of how this particular painting changed hands to end up in
Russia? Names of dealers, etc.?

I don't think it is the case that this painting was looted by the
Nazis, it was, however, along with other paintings looted by the
Soviet Union from the Gerstenberg/Scharf collection, Berlin, during
the post-war years; as were many other German-owned artworks. Whereas,
property taken from national collections has to be returned under
agreements between the German and Russian states, property from
private collections (like this Degas) is in a different category, and
has so far not been returned. See the following website on
"Restitution by Russia of Works of Art Removed from German Territory
at the End of the Second World War"
http://www.ejil.org/journal/Vol7/No1/art4-03.html

Thank you geof. The entire subject fascinates me.  In researching this
myself, I read where a member of the Wildenstein family, said that
Margarete Scharf 'sold them' or else, put Place de la Concorde and
other works, in his care, so as to protect them from destruction
and/or theft.  However, if this Wildenstein is related to Georges
Wildenstein, who has been documented in our National Archives, as
having done business with the Nazi's...whom are we really to believe?
I would love to trace the trip, so to speak...but, online, there are
varying accounts as to the 'handling' of this particular collection.
According to my research, Place de la Concorde was thought destroyed
by Allied bombing during WWII...only to turn up, to everyone's
surprise and delight, in the Hermitage in 1990's.  Thank you again,
geof, for your comment. It helps clear SOME of the mystery.