hautemarne

Henri Philippe Benoni Omer Joseph Pétain (24 April 1856 – 23 July 1951), generally known as Philippe Pétain (French: [fi.lip pe.tɛ̃]) or Marshal Pétain (Maréchal Pétain), was a French general who reached the distinction of Marshal of France, and was later Chief of State of Vichy France (Chef de l'État Français), from 1940 to 1944. en.wikipedia.org/wiki/Philippe_P%C3%A9tain

Caption in Catalogue of official A.E.F. photographs [1919]: "Marshal Petain, commander in chief of French Army. General Headquarters, Chaumont, Haute Marne, France. January 14. 1919." archive.org/stream/cu31924027944598#page/n437/mode/2up

Probably same occasion as

"General Charles Pelot Summerall (March 4, 1867 – May 14, 1955) was a senior United States Army officer. He served in World War I, as one of the first commanders of the 1st Infantry Division ("The Big Red One"), and was Army Chief of Staff from 1926 and 1930. He was also the President of The Citadel between 1931 and 1953." en.wikipedia.org/wiki/Charles_Pelot_Summerall

From Wikipedia article: "Summerall commanded IX and IV Corps and served on the American Peace Commission at the Peace Conference in 1919"

This photo is quite likely to have been taken in France. Le Meschacébé., March 08, 1919, page 2 chroniclingamerica.loc.gov/lccn/sn86079080/1919-03-08/ed-... has a photo of him among a group of American generals honored by the French. The same photo appeared in a number of American papers, including he Daily Ardmoreite., February 15, 1919, page 1. chroniclingamerica.loc.gov/lccn/sn85042303/1919-02-15/ed-...

Confirming that it was taken in France. From Catalogue of official A.E.F. photographs, p 425 archive.org/stream/cu31924027944598/#page/n429/mode/2up 39279 [518D8]. Maj. Gen. Charles P. Summerall, commanding general Fifth Army Corps, with his staff and commanders of divisions in Fifth Army Corps at present time. Seated, left to right: Maj. Gen. George B. Duncan, commanding general. Eighty-second Division ; Maj. Gen. Charles G. Morton, commanding general. Twenty-ninth Division ; Maj. Gen. Charles P. Summerall, commanding general, Fifth Army Corps ; Maj. Gen. Harry Hale, commanding general. Twenty-sixth Division ; Brig. Gen. Wilson B. Burtt, chief of staff. Fifth Army Corps. Standing, left to right : Col. A. W. Foreman, assistant chief of staff, G-1, Fifth Army Corps ; Col. G. M. Russell, G-2; Col.- Gordon Jonston, chief of staff, Eighty-second Division ; Col. T. H. Emerson, G-3, Fifth Army Corps; Col. Sidney A. Cloman, chief of staff. Twenty-ninth Division ; Col. Duncan K. Major, Jr., chief of staff. Twenty-sixth Division. Nogent Le Roi, Hte. Marne, France. November 26, 1918.

Caption in Catalogue of official A.E.F. photographs, 1919: "39680 [1862N9]. Gen. John J. Pershing shaking hands with Miss Goodwin, Y. M. C. A. worker. General Headquarters, Chaumont, Haute Marne, France. January 14, 1919." archive.org/stream/cu31924027944598#page/n437/mode/2up