Mr. Obama had refused to meet with Mr. Putin during his four-day trip to Europe, even though his French, German and British counterparts all scheduled individual meetings with the Russian leader here in France. Still, aides had not ruled out the possibility of an informal conversation much like the one that evidently took place out of the public eye on the sidelines of the ceremonial luncheon.
The two were first seen together behind the chateau here as leaders from around Europe and elsewhere gathered to take a group photograph. President Franςois Hollande of France stood in the middle with Queen Elizabeth II to his right and Mr. Obama to her right. To Mr. Hollande’s left was Queen Margrethe II of Denmark and to her left was Mr. Putin.
Thus separated by three people, Mr. Obama and Mr. Putin busied themselves talking with others. Mr. Obama jovially greeted Chancellor Angela Merkel of Germany, kissing her on both cheeks. When the photograph was taken and the group began wandering into the chateau for lunch, Mr. Obama lingered behind, making sure that Queen Elizabeth, who was moving gingerly, got up the stairs and path all right.
At one point as the crowd moved slowly toward the building, Mr. Obama was right behind Mr. Putin and could have tapped him on the shoulder if he wanted to but instead focused his attention elsewhere, as if not noticing who was there. Inside the chateau, the leaders had lunch around a horseshoe table, seated in the same order as in the photograph, with Mr. Obama and Mr. Putin separated by the same three people.