I saw it at an exhibit in new orleans last year called femme femme femme. The painting is of a man and a woman and they look like they are talking with their backs to the viewer. I cant remember but i think they are on a bridge or balcony. I know this may be vague but it has been a year since i have seen it.
Could it possibly have been any of these? Tissot - -Querelle d'amoureux [Lover's tiff]
-By the Thames at Richmond (Declaration of Love)
-On the Europe Bridge
Caillebotte -
-View Across a Balcony
